"Welcome to Korea" was a 2-episode story arc, the 73rd and 74th episodes of the M*A*S*H television series, and first two episodes of the fourth season of the series. First aired on September 12, 1975, the series' first 60 minute episode (double the normal time) was most notable for its off-screen departure of the character of Captain Trapper John McIntyre (played by Wayne Rogers), and his replacement by the freshly drafted Captain B.J. Hunnicutt (played by Mike Farrell).

"Welcome to Korea" features the first depiction of the 4077th MASH following the death of former unit commander Lieutenant Colonel Henry Blake (played by McLean Stevenson), and with Major Frank Burns (played by Larry Linville) in charge. Another change of command is previewed, in the form of a short appearance by Harry Morgan as Colonel Sherman T. Potter; he would be fully introduced in the following episode, "Change of Command".

The episode, which was written by Everett Greenbaum, Jim Fritzell, and series creator Larry Gelbart and directed by Gene Reynolds, won two Emmy awards in 1976: "Outstanding Directing in a Comedy Series" for Reynolds, and "Outstanding Achievement in Film Editing for Entertainment Programming in a Comedy Series". After the joint departures of Stevenson and Rogers, one third of the original cast, after the series' third season, there was a great deal of uncertainty about the direction and future for the series; "Welcome to Korea" was notable for beginning a generalized move for the series away from a sitcom to a dramedy.