The primary series, which ran from 26 January 1994 to 25 November 1998 after its pilot episode was broadcast on 22 February 1993, was the first truly successful American futuristic, space-oriented science fiction television series outside of the Star Trekfranchise. Like Trek, there have been several attempts to create viable spinoff properties, including six made-for-TV movies and the short-lived series Crusade, featuring Daniel Dae Kim, Marjean Holden, and Tracy Scoggins. Enjoying a considerable measure of success while the original source series was being produced and aired, the franchise eventually faded into obscurity due to a combination of intentional sabotage by TNT, poorly considered money-saving maneuvers by Warner Bros. (including but not limited to the decision to save $5,000 per season and in the process make it impossible to produce a high definition version of the show, and the decision to produce wide screen versions of effects shots by recompositing later, which proved impossible after assets were lost), and internal Warner Bros. studio politics. The show continues to be available on Standard Definition DVD and has a cult following, but has not been syndicated since the early 2000s, making it hard for potential fans to discover and preventing a fan driven comeback such as was enjoyed by Star Trek.
The series was widely acclaimed for its ambitious writing, much of it by Straczynski himself, who endeavored to tell a complex, predetermined epic story arc, in the form of the Shadow War, over the series' entire run, as opposed to the episodic (or two-part episodes at the most) story format until then employed for science fiction television series. It thereby convincingly dispelled the hitherto held belief by Hollywood studios that television audiences lacked the attention span to remain interested in a science fiction series format thus conceived. In service of that goal, the show had an innovative visual style, taking advantage of advances in computer animation to create spectacular fantastic visual effects (VFX) on an economical budget, most notably computer generated imagery (CGI), pioneered by Foundation Imaging, who later also provided VFX for the Star Trek franchise. The use of CGI in the series was a definitive breakthrough in creating VFX for television, much as the movie Jurassic Park was for cinema; it went on to become the primary technique.
J. Michael Straczynski began working on the Babylon 5 concept in 1986.  In 1987, he began pitching it, with a script for the pilot and conceptual artwork, to Hollywood executives.  He pitched the program (with pilot script, artwork, series bible, character descriptions, and synopses for approximately twenty-two episodes) to Paramount executives in 1989.  The series was greenlit by Warner Bros. in November 1991. 
Straczynski has suggested that Paramount TV development executives may have "guided" the development of Deep Space Nine with the intention of co-opting Babylon 5.  He has, however, been careful to point out that he does not believe that Berman or Piller were aware of the Babylon 5 concept when they were developing Deep Space Nine, or that they deliberately ripped off Babylon 5. If Straczynski had been right in his unspoken suspicions, then this had been a case of history repeating itself, but then with Star Trek on the receiving end; in April 1964 Gene Roddenberry and Oscar Katz presented the Star Trek is... pitch to television studio CBS, which was rejected by the studio, but not after been thoroughly questioned about it. It turned out that CBS had its own science fiction show, Lost in Space, under development at that time, and both Katz and Roddenberry in particular were convinced that CBS had picked their brains. (Star Trek Creator: The Authorized Biography of Gene Roddenberry) Like Deep Space Nine and Babylon 5, Star Trek: The Original Series and Lost in Space became science fiction franchise contenders in their day.
Despite his diplomatic stance however, Straczynski could not refrain from pointing out a number of similarities between Babylon 5 and Deep Space Nine, particularly their respective pilot episodes:
Straczynski also commented on what he perceived to be similarities in set and prosthetic designs, as well as the notion – mentioned in Deep Space Nine publicity but rarely acknowledged directly in the program itself – that the holosuites in Quark's would act as a virtual bordello.  In 1993, Straczynski noted a striking similarity between the just-aired Deep Space Nine episode "The Homecoming", in which Quark is branded on the head by the xenophobic and radical Circle, and the Babylon 5 episode "The War Prayer" (then in post-production), in which a Minbari is branded on the head by the xenophobic and radical Homeguard; he emphasized that no one on the Babylon 5 staff knew of the DS9 plot point until "The Homecoming" aired, by which point filming on "The War Prayer" had been completed. 
Later, in 1996, Straczynski said:
"Sometimes it does bother me, and I wonder about what the heck's going on, when I see the only other space station series doing a big arc about alien forces infiltrating Earth government, and brewing civil war on Earth, at the *exact same moment* that we're doing it on our show; earlier, later, fine, but that they'd do basically the same thing at the same time feels like another attempt to co-opt what we're doing on this show. (Not copy; co-opt, which happens all the time. ....) If you kinda know the direction someone else is going, you try to jump ahead and get there first, so that the other either loses impact, or is considered simply an imitation. (Which is one reason why DS9 was hurried through post production to get it on the air a few weeks before B5's pilot, I suspect.)
Are we being co-opted? I dunno. When I hear that there's a red-headed woman character on DS9 named Leeta (pronounced the same as Lyta); when I see them doing the same kind of arc we're doing but getting it out a little earlier, I will confess it does give me pause sometimes. I try to think the best under these conditions. For now, I'm asuming [sic] it's all just coincidence."
After seeing "Homefront" and "Paradise Lost", Straczynski recognized that the story was an homage to the film Seven Days in May, implicitly withdrawing this criticism. 
In the face of the rivalry, Majel Barrett-Roddenberry agreed to a guest appearance on Babylon 5 as a gesture of goodwill to encourage a reconciliation between the fandoms.  She played a widow of the late Centauri Emperor, whose greatness and vision for peace had not been fully appreciated within his own lifetime. She foresaw Ambassador Mollari's rise to power.
Despite the signature importance of effects house Foundation Imagining had been for Babylon 5, the company was due to the above-mentioned unsavory studio politics let go from the production after its third season in 1995, leaving the company in dire straits. Yet, the services of the company were picked up the same year by the Star Trek franchise for their production Star Trek: Voyager, after its CGI vendor Amblin Imaging went defunct. However there were initial trepidations to do so, as Foundation's visual style was so associated with that of Babylon 5. (The Official Star Trek: Voyager Magazine issue 16, p. 35) In this regard David Livingston has observed, commenting on the use of computer-generated imagery in "Explorers", "We were reluctant to do computer graphics, but Peter Lauritson finally came around. He recognized how valuable it is. You can do more stuff with the ship, but you have to do it right. Not to pick on other shows, but Babylon 5 looks like computer-generated imagery. On Voyager and Deep Space Nine, you may not know some of these shots are not motion-control shots. They're really, really good if done properly. You have to spend a couple of extra bucks and get really good artists, but CGI just allows you to do more and you can build more elements into the shots". (Captains' Logs Supplemental - The Unauthorized Guide to the New Trek Voyages)
Additionally, Deep Space Nine Visual Effects Supervisor Gary Hutzel has stated, "My particular focus for our show, for Star Trek: Deep Space Nine, is that it should be a visual effects leader; we should never follow, we should never do what's been done before. CGI has certainly been used to various different degrees of success on Star Trek: Voyager, but I think it's still a hit-and-miss prospect, so I'm not interested in doing it." (Star Trek Monthly issue 31, p. 26) Still, Foundation has amply proven their mettle for Star Trek, even increasingly providing effects for Deep Space Nine's last two seasons as well, continuing to do so for the first season of Star Trek: Enterprise. Nonetheless, some Babylon 5 influences crept into the designs of some of the ships featured in Voyager; the designs of the Species 8472 bio-ship and Krenim weapon ship for example, echoed those of the Vorlon ships and the titular Babylon 5 station respectively, unsurprisingly perhaps, as these were (co-)designed by Steve Burg and Foundation CEO Ron Thornton respectively for either production.
Even though Babylon 5 has somewhat receded in the consciousness of science fiction fans, Star Trek's current owner, CBS Television Studios (or rather CBS Corporation), has not been able to refrain themselves of reminding television audiences of the fierce competition that existed at the time between the two franchise, or let the issue slide. In their hugely popular (and Star Trek friendly) sitcom series The Big Bang Theory, series regular Sheldon Cooper occasionally expresses his deep disdain for Babylon 5, while his roommate Leonard Hofstadter loves the series, yet losing each and every argument they have over the series. His most outspoken criticism was voiced in that series' third season episode "The Large Hadron Collision" (S03E15, 2010), where he stated that Babylon 5 "(...)failed as drama, science fiction and is hopelessly derivative", referring to the battle that raged at the time between that series and Deep Space Nine – and in the process implicitly accusing Babylon 5 of plagiarizing Deep Space Nine. The stance taken in The Big Bang Theory has irked the still existing Babylon 5 fanbase, but has also enticed some science fiction fans, new to the series, to check out the series for themselves, because of Sheldon's aversion. 
In the Babylon 5 episode "There All the Honor Lies" (written by Peter David), Commander Ivanova protests an attempt to sell "Babylon 5" merchandise on the station, saying, "We're not some Deep Space franchise – this place is about something!" David expected the line to be cut, but producer Straczynski insisted that it be kept, because it was "fall-down funny." David replied, "You people really ARE dangerous over there, aren't you?" 
In the episode "Voices of Authority", when an Earthgov political representative attempts to seduce Captain Sheridan, Ivanova quips, "Congratulations, captain... I believe you are about to go where everyone has gone before."
A blooper from the episode "Severed Dreams" has Bruce McGill's character, when asked where Robert Foxworth's character General Hague was, say "General Hague... is doing Deep Space Nine. It seems he was double-booked by his agent and nothing could be done." 
Actors who have appeared in Star Trek and Babylon 5Edit
↑Robert Foxworth's characters on Babylon 5 and Deep Space Nine were very similar: both were high-ranking military officers who led coup attempts against civilian governments based on Earth (although the Babylon 5coup was against a totalitarian regime). Both attempts failed. Foxworth had already been booked for a third appearance as General Hague on Babylon 5 when his agent accepted the Deep Space Nine role, which was filming at the same time. In response, J. Michael Straczynski killed off the character of General Hague off-screen (saying, "Never honk off the writer"). 
↑McGill was cast as a new character to replace the role of General Hague, played by Robert Foxworth, who had opted to appear in a two-part episode Deep Space Nine instead (see above).
Production personnel who have worked on both franchisesEdit
note: Not listed are the staffers of CGI company Foundation Imaging, the vast majority of the original 1993-1995 line-up having also worked on both franchises. See main article for staff listing.