There is some confusion surrounding the last episode of season 4, due to the late announcement of the renewal of Babylon5 for a 5th season. JMS had the following to say about the final episode (which if there'd been no season 5 could have played at the end of season 4):

" Re: 422...this one is a stand-alone episode which I specifically designed in order to have the flexibility to air it either as 422 or as 522, depending on what happens. This way if year 4 is all there is, we get to where we need to get; if we get year 5, then we shoot 501 and air it in 422's spot, and air 422 in place of 522.

[[May/24]] 501 isn't written yet, won't be until we get the final word. We could certainly get it finished in time for the US airing in 422's spot, and as for getting it done in the UK, assuming a mid-July start for season 4, means you'd run episodes through late October/early November so again you're okay.

[[May/25]] The final 4 would get aired in October. If there's no season 5, then the fourth one aired is 422, "Sleeping in Light."

Thanks to the renewal of B5 for a 5th year, the final episode of season 4 is actually the first of the season 5 production run. The final episode of season 5 was actually filmed during season 4's production run.

23 Jul 1997 - "Hour of The Wolf"

Londo discovers that Emperor Cartagia has struck a disturbing deal. G'Kar sets out in search of Garibaldi. Ivanova and Lyta head towards Z'ha'dum.

30 Jul 1997 - "What Ever Happened to Mr. Garibaldi?"

G'Kar tries to avoid capture by the Centauri while continuing his search. Delenn urges the Rangers to strike against the Shadows.

6 Aug 1997 - "The Summoning"

Zack makes a discovery in the search for Garibaldi. Delenn's plan to attack the Shadows runs into trouble. Ivanova and Marcus attempt to solicit aid from more First Ones.

13 Aug 1997 - "Falling Toward Apotheosis"

The Vorlons step up their battle against the Shadows. Londo uncovers a new wrinkle in his plan to unseat Emperor Cartagia. Garibaldi is asked to remove Kosh from the station. Delenn gets a surprise.

20 Aug 1997 - "The Long Night"

As the Army of Light prepares to strike against the Shadows, Londo and Vir continue to plot Cartagia's downfall. Ivanova and Lorien look for more First Ones. The Shadows unleash a terrible new weapon.

27 Aug 1997 - "Into The Fire"

The Army of Light moves against the Shadows.Londo learns some surprising information about Morden.

3 Sep 1997 - "Epiphanies"

Bester arrives with news of an Earth Alliance plan to further isolate Babylon 5.Garibaldi delivers some surprising news to Sheridan.

10 Sep 1997 - "The Illusion of Truth"

After suspicious news about Sheridan's father surfaces, ISN sends a team to do a second story about Babylon 5.

17 Sep 1997 - "Atonement"

Delenn is recalled to Minbar to resolve a problem concerning her relationship with Sheridan, and must finally face up to her role in the Earth-Minbari War. Sheridan sends Marcus and Franklin to Mars on a secret mission.

24 Sep 1997 - "Racing Mars"

Franklin and Marcus arrive on Mars to begin their undercover mission. Sheridan confronts Garibaldi about his behavior.

1 Oct 1997 - "Lines of Communication"

Franklin and Marcus try to convince the leaders of the resistance to go along with Sheridan's plan to unseat Clark. Delenn investigates a series of attacks on Minbari allies. Minbar begins to slide toward civil war.

8 Oct 1997 - "Conflicts of Interests"

Garibaldi starts a new job on Mars. The resistance's counter-propaganda broadcasts begin. Sheridan proposes a plan to protect the Non-Aligned Worlds from raiders.

15 Oct 1997 - "Rumours, Bargains and Lies"

Sheridan tricks the League of Non-Aligned Worlds into accepting his proposed defense pact. Delenn tries to work with an old rival to defuse a brewing Minbari civil war.

22 Oct 1997 - "Moments of Transition"

The warrior caste demands Delenn's surrender. Bester makes an offer to an increasingly desperate Lyta. Sheridan is compelled to act after receiving horrible news from Ivanova.

29 Oct 1997 - "No Surrender, No Retreat"

Sheridan's forces attempt to liberate Proxima 3. Londo tries to enlist G'Kar's aid in backing Sheridan against Earth.

6 Nov 1997 - "The Exercise of Vital Powers"

Garibaldi arrives on Mars and meets William Edgars. Lyta helps Franklin in an attempt to make contact with the frozen telepaths.

13 Nov 1997 - "The Face of the Enemy"

Sheridan's search for his father leads him into danger on Mars. Lyta warns Franklin of an impending clash between telepaths and mundanes. Garibaldi chooses between loyalty to Sheridan and to Edgars.

20 Nov 1997 - "Intersections in Real Time"

Sheridan faces an inquisitor from Earthdome.

27 Nov 1997 - "Between the Darkness and the Light"

Garibaldi is captured by the Mars Resistance. Ivanova's fleet clashes with Clark's forces. A plan to free Sheridan is launched.

4 Dec 1997 - "Endgame"

Sheridan's forces make their final strike. Marcus weighs a vital decision.

11 Dec 1997 - "Rising Star"

Earthgov decides Sheridan's fate. Delenn makes a remarkable proposition to the League of Non-Aligned Worlds. Garibaldi continues his search.

18 Dec 1997 - "The Deconstruction of Falling Stars" Season Finale

A look back at the impact of Babylon 5 from 100, 1000, and 1000000 years in the future.