Flatow was born in Germany and emigrated to Australia. He was City of Sydney Champion eleven times (1963, 1967, 1968 (jointly), 1969, 1970, 1972, 1975 (jointly), 1981 (jointly), 1982, 1983, and 1985),[5] and won the Australian Chess Championship in Sydney 1969/70.[2][6] He also won the Doeberl Cup in Canberra three times (1970 (jointly), 1972, 1979).[7]
He twice played for Australia in Chess Olympiads (Lugano 1968 and Skopje 1972).[8]