Past research suggests links between an adolescent's age and sex and parental monitoring, as well as between parental monitoring and externalizing behavior; however, there is little research on the potential mediating role of parental monitoring on the relationship of age and sex to problem behaviors. The final sample for this study consisted of 205 African-American young adolescents and their parents, who participated in a study of the daily life experiences of urban African-American youth. The participants were in the fifth through the eighth grades at schools with student bodies that were predominantly African-American. Forty-five percent of the students were males. The sample was drawn from eight low-income to middle-income and working-class communities in a large urban setting. As part of the larger study of daily experience and well-being, data were collected through the Experience Sampling Method to obtain a diary account of the young adolescents' objective and subjective experiences, as well as through questionnaire measures. Grade was used as a proxy for age. To assess children's perceptions of parental monitoring, students completed an adapted version of the Parental Attitude measure. The measure of parents' perceptions of parental monitoring consisted of a subset of four questions from Kalil and Eccles (1994) questionnaire. The questions asked parents if they were monitoring their child's whereabouts. Adolescents completed an abbreviated and revised version of Self-Report Delinquency Scale. Four items measured alcohol and drug use. Two subscales of the Child Behavior Checklist provided parent reports of the child's delinquent and aggressive behaviors. 3 tables, 3 figures, and 73 references