The series follows a team of doctors and support staff stationed at the "4077th Mobile Army Surgical Hospital" in Uijeongbu, South Korea, during the Korean War.

The show's title sequence features an instrumental-only version of "Suicide Is Painless". The song was originally written for the movie version of M*A*S*H.

Lt. Colonel Henry Blake served as the happy-go-lucky, easygoing commanding officer of the 4077th during the first three seasons.

Radar has almost super-human hearing and is able to hear incoming helicopters before anyone else. It is this ability, along with his uncanny knack for finishing his commander's sentences, that earns him the nickname "Radar".

The name "Hot Lips" originates from an infamous scene in M*A*S*H, the movie. During sex with Frank, Margaret--who is unaware that the public address microphone has been planted beneath their cot, broadcasting graphic details of their sexual encounter throughout the camp--screams "Yes Frank! Oh yes, kiss my hot lips."

In the early seasons, Klinger is endlessly trying to get a psychiatric discharge, or "Section Eight", mainly by cross-dressing. B.J. Hunnicutt remarks that by always trying to get out, Klinger is actually the only sane one in camp, while everyone else is crazy for accepting their situation.

Oliver Harmon "Spearchucker" Jones was dropped from the show after just six episodes. He plays his most significant role in "The Moose", in which he helps to convince a young Korean servant girl she is free after Hawkeye wins her in a card game.

In "Lil", Hawkeye tries to figure out what B.J.'s initials stand for, but all the paperwork simply lists him as B.J. At the end of the episode, B.J. reveals that his parents were named Bea and Jay, hence, B.J.

At the beginning of the series, the Swamp held four doctors: Hawkeye, Trapper, "Spearchucker" Jones and Frank Burns. After the departure of Jones, the number of residents dropped to three and remained so until the end of the series. B.J. moved in after the departure of Trapper and Winchester after the departure of Burns.

In the final scene of the season finale, Radar enters the operating room without the required surgical mask and informs the staff that Henry Blake's plane has been shot down in the Sea of Japan and that there were no survivors. It was one of the most shocking moments in television history for the audience and even the cast. None of the actors were told of the news before the final scene.