Individuals participate in sport events with different motivations. One of the elements that influence physical activity participation is a difference in cultures. So, in order to test this claim, 279 Iranian and 310 Russian students were investigated. They were from Guilan, Mazandaran, Gorgan, and Russian universities who attended the Third Sport Olympiad in Caspian Sea in Summer 2004. A researcher – made questionnaire was used to determine the students’ viewpoints, and a standard questionnaire was used to measure their motivations. Reliability of questionnaires was between 0.79 and 0.86 and data were collected and analyzed by Kruskall-Wallis test. The minimal level of significance was set at P<0.05.The results showed that Iranian and Russian students' viewpoints on the effect of cognitive development and general knowledge of sport activity engagement were very similar. However, regarding the effect of socio-emotional development, Iranian students emphasized social role while the emotional role was emphasized by Russian students. Sport competitions, challenge, and social experience of involvement (Social interactions) were the three reasons of Russian students for their regular exercise. But in Iranian students, health and physical fitness, enjoyment, physical appearance, relaxation and release from tension were important reasons for regular exercise.