I guess that depends on whether you consider Sister Ana (Linda Dangcil), who was in about half the episodes, as part of the main cast.
ETA: Oh, yeah, I guess there’s even a better candidate in Alejandro Rey.
I was hoping Emergency! ,ight do the trick, but although the paramedics are alive and kicking, I see that both Dr. Early and Nurse Julie have flatlined.
I was thinking about the series Room 222. For some reason, I heard about a year ago that Michael Constantine was still alive. I checked and saw he’s still alive (at age 87).
But Lloyd Haynes died back in 1986 at the age of 52.
William Boyett didn’t appear in every episode and he wasn’t listed in the title credits, so I figure he counted as a recurring guest star rather than a regular.
The actors who played Dr. Early (Bobby Troupe) and Nurse Dixie McCall (Julie London) were married to each other in real life.
I used to love that show, seeing what stupid thing Johnny Gage would do and seeing how half of Los Angeles seemed to be burning each week.
If Morey Amsterdam were still alive*, The Dick Van Dyke Show (premiered in 1961) would be a strong contender. DVD, MTM, Rose Marie and Larry Mathews are all still alive.
*It’s a lot to ask for: he’d be 107.
Well, The Bill Cosby Show (the wiki page list BC as the only cast member) premiered in 1969 and he’s still around…
Zev Steinhardt
Richard Deacon (Mel Cooley) and Jerry Paris (Jerry Helper) are both dead as well. In fact, they and Morey were dead when then made the Dick Van Dyke reunion special in 2004, and the show mentioned that their characters had died as well. (The plot involved Alan Brady wanting Rob to write his eulogy, since he had given the eulogy at Buddy’s, Mel’s, and Jerry’s funerals.)
Jesuchristo, this is a depressing thread! 
Sure is. I just looked at a list of 70s TV shows and I see a whole lot of dead people.
Please Don’t Eat the Daisies premiered in 1965. Mark Miller is 89 and Patricia Crowley is 81, but they’re still alive, as are the actors who played their kids.
Martin Milner and George Maharis from Route 66 (1960) are still alive, but Glenn Corbett, who replaced Maharis, is dead.
The three young stars of The Mod Squad (1968-1973) - Michael Cole, Clarence Williams III, and Peggy Lipton - are still alive. However the show’s opening credits say “Also Starring Tige Andrews” and he is no longer with us.
It’s time for a reunion show called Please Don’t Push Up the Daisies!
(I’m sorry).
The Avengers, perhaps? Depending on how far back you want to go, four out of the five listed as “Starring” in the Wiki article are still avenging. The original star from the first and only season, Ian Hendry, died, but to me the only two that count are Steed and Mrs Peel. Even still, with Steed in the lead role starting in the second year (technically, he was solo in the last episode of the first year) that brings it back to 1962.
Yeah, they kind of fired him I think for his drug problem. Wesley replaced him and was awesome.
Andy Hallett was a bigger shock, since he was healthy. He had a dental problem and an infection went to his heart. Very sad.
Don’t forget Honor Blackman (Mrs Cathy Gale). She’s still alive and will turn 90 in August.
i thought of this show but I was certain I remembered hearing about Patrick MacNee’s death a few years ago. But I see I’m wrong and he’s still alive at the age of 93.
I think we have a winner here.
Yup. I thought I had it with The Rookies. Even the chief is still alive…but the white guy with curly brown/blonde hair isn’t.
I was going to vote for “The Doris Day Show” regulars as having decent longevity – Doris Day was the only regular for all five seasons (1968-73), and she’s still around. So are Philip Brown, James Hampton, Rose Marie, Jackie Joseph, Paul Smith, Naomi Stevens, Bernie Kopell and Kaye Ballard. Denver Pyle, McLean Stevenson, John Dehner, Billy DeWolfe and Peter Lawford are gone, but surely Todd Starke, who (with Brown) played one of her sons, is still alive, yes?
Nope. Died in a 1983 motorcycle accident at age 21.
ETA: Jean Byron died in 2006, but the other regulars of “The Patty Duke Show” seem to be alive.