This study was conducted to provide standardization data and information on the reliability and factorial validity of the recently developed Adolescent Activities Checklist (AAC). A total of 563 adolescents in grades 7 through 12 served as subjects. Significant main effects for gender, race, and grade were obtained in a multivariate analysis of variance. On the basis of this information, standardization data were established for these three variables. Further investigation indicated that the internal consistency of the AAC was high. In addition, results of a principal components analysis conducted on the frequencies of the Unpleasant and Pleasant Activities subscales revealed four and three factors, respectively. For unpleasant activities, the major dimensions were found to occur in three situations--namely, social interactions, family situations, and school situations. Stressful events also occurred as one of the four unpleasant activities dimensions. For pleasant activities, three dimensions appeared: heterosocial behavior, reinforcing interpersonal situations, and social reinforcement.