The poll, conducted by the British Film Institute, asked 1,600 programme-makers, TV critics, writers and executives to give their professional opinions and personal tastes.
Launched by TV interviewer Michael Parkinson, the TV 100 list spans nearly 50 years of television, and includes drama, comedy, variety, documentaries, light entertainment and children's shows.
Fawlty Towers, which starred John Cleese as a deranged hotelier, was first shown in 1975 and continued to enjoy high ratings during recent re-runs.
BBC successes
The classic comedy series is one of several BBC productions in the top 10, including the 1966 drama Cathy Come Home, the long-running sci-fi series Doctor Who, Monty Python's Flying Circus and perennial children's favourite Blue Peter.
Surprisingly, the hugely popular BBC comedy Only Fools and Horses (1981-1996), which was a guaranteed ratings winner at Christmas for several years, failed to make the top 20.
ITV's only top 10 successes were drama productions The Naked Civil Servant (1975, Thames), and Brideshead Revisited (1981, Granada).
Some of the programmes appeared on both ITV and the BBC, including University Challenge, This Is Your Life and Thunderbirds.
Coronation Street was the only soap opera to make the list, while comedy classics Dad's Army and The Morecambe & Wise Show fared better than modern-day counterparts like Absolutely Fabulous and Blackadder.
Parkinson, whose chat show of the same name featured at number eight, said: "The particular significance of this list of programmes is that it reflects the votes of the television industry - those involved in programme-making - and they can be a tough audience to satisfy."
BFI director John Teckman added: "The BFI TV 100 is a wonderful celebration of quintessentially British programmes which have entertained us over the years. It serves as a timely reminder that we have a television heritage to be proud of."
The Top 20
(The complete top 100 can be found on the BFI's website)