The present study was designed to identify characteristics of the students who were the influentials (influential persons who maintain involvement in a certain activity) of intramural sports programs and to describe the flow of such influence. The data on which the article is based were taken from the inquiry on intramural sports events held at Tottori University in 1979, The procedures of analysis applied to this study, roughly speaking, can be seen in E. Katz and P. F. Lazarsfeld (1955). The results may be Summarized in the following way: 1) With regard to evaluating the impact of various influences in the decision-making process associate with intramural participation, the impact of informal personal advice was assessed by most of the respondents to be greater than the impact of formal communication media. 2) The data show that habitual exercisers are more likely to function as participation leaders and that the influence flows from them to the less active strata of the students. However, at the same time, it seems reasonable to infer that the advice circulations within the same sports life strata are more important as a determinant of participation in intramurals. 3) In considering the profiles of the intramural sports leaders, there is an indication that the students who are selected for intercollegiate varsity teams may not play the part of leaders in intramurals, despite the fact that there is a higher proportion of leadership among the habitual exercisers. 4) Leaders are influenced more by the intramural publicity through such posters, handbills, or pamphlets, than are the non-leaders.