The purpose of this study was to examine the impact of the "C" average rule on student achievement at Stagg High School, Stockton, California. This study particularly addressed the issue of whether there were significant differences between athletes' grade point averages (GPA) before implementation of the policy and after. In addition, the study included assessing differences in attendance patterns of the athletes. The 1981-82 school year was identified as the year prior to implementation of the "C" average-rule. The 1982-83 school year was considered the implementation year and, finally, the 1983-84 school year was identified as the year after the implementation of the "C" average rule.For an athlete to be included in this study, a grade point average must have been available for at least one of the three athletic seasons during the year preceding the implementation of the "C" average policy. In addition, each athlete must have participated in athletics subsequent to the 1981-82 year. Thus, each athlete was required to have GPA and attendance data for two particular points in time over the three years included in the study. The total number of male and female athletes for whom all analyses were done was five hundred sixty-two. These athletes represented the four major ethnic groups, Black, Asian, White and Hispanic. All data were organized to correspond with the fall, winter, and spring athletic seasons. Grade point averages were recorded from report cards and transcripts. Attendance data were recorded from individual attendance sheets maintained at the school site. Ethnicity and gender were recorded based upon school emergency cards. Ten questions provided the focus of the study. Each of the ten questions to be answered asked for a comparison between GPA or attendance prior to implementation of the "C" average rule and subsequent to it. Means for the particular paired groups were obtained, and the t test for related measures was calculated. The .1 0 level was used to determine significance. While some significant differences were noted, usually favoring pre policy data, generally speaking, it appeared that the policy had no direct impact upon either grade point averages or attendance rates. The study was not done in a way to establish a cause and effect relationship, but from a practical perspective, it does not appear that either GPA or attendance was seriously affected. Recommendations for future studies are made including replication of this study now that California has implemented the "C" average rule statewide, as well as in a variety of other high school settings.