This paper presents and discusses evidence about the sport careers of representative samples of 31-37 year olds from the capital city and a comparator region in each of the three South Caucasus countries--Armenia, Azerbaijan and Georgia. This is one of the few surveys to measure sport participation that allows change over time at the aggregate and individual levels to be distinguished. The evidence suggests that many differences in sport participation rates that are commonly attributed to circumstances and experiences after age 16 (higher education, for example) already exist at age 16, and that family cultures are the source of crucial predispositions to participate which have lasting effects. The evidence, from countries that up to 1991 shared the Soviet education and sport systems, also suggests that ethnic/national cultures that predate communism have outlived communism and are now a major explanation of inter-country differences in rates of sport participation in the South Caucasus. Finally, the evidence indicates that sport facilities do indeed make a difference, but only by enabling those who are predisposed to take part in sport. (Contains 10 figures.)