This evening in New York, Mamma Mia will play its 2,845th performance, which will rank it as the 16th longest-running Broadway show of all time. Hello, Dolly! previously held that honor with its 2,844 performances.
One could argue, of course, that Mamma Mia enjoys a big advantage over Hello, Dolly! in that Mamma Mia is pretty much a starless show. People went to see Hello, Dolly! because Carol was in it…or Pearl or Ethel or some other huge force of theatrical nature. The long run on a star-driven show is often dependent on how long the star will stick around and drive. If Nathan Lane and Matthew Broderick were still doing The Producers, it might still be running.
But the achievement of Mamma Mia is still quite impressive. A few months ago, it passed My Fair Lady..and at the rate it's going, it will almost certainly outlast Tobacco Road (3182 performances), Life With Father (3224), the original Fiddler on the Roof (3242), the original Grease (3388) and the original 42nd Street (3486). If and when it eclipses the last of these, it will be the 11th longest-running Broadway show of all time. After that, it just might stick around long enough to beat Miss Saigon (4097) and crack the Top Ten. That would take three more years but since it's still selling out after seven years, that seems quite possible.
After that, it gets rougher. The 9th, 8th and 7th longest-runs (The Lion King, the revival of Chicago and then Rent, which closes this weekend) are all at least 1600 performances ahead of Mamma Mia and still running. If you figure roughly 416 performances per year, for Mamma Mia to overtake Lion King, Lion King would have to close and then Mamma Mia would have to run another four years. Possible, not probable.
Before anyone asks: The current longest-running show on Broadway is Phantom of the Opera, which has been there since 1988 and has played close to 8600 performances. It not only has that distinction but will probably have it for the rest of our lives.