This study reports grade, gender, and environmental (school structure) differences in self-reported use of tobacco, alcohol, and marijuana among urban black adolescents. Among the results are the following: (1) an equal percentage of males and females reported having "tried" cigarettes and alcohol; (2) males reportedly smoked more cigarettes within a 30-day period than females; (3) an equal number of males and females reported drinking alcohol within the same period; (4) a much greater percentage of males reported having tried chewing tobacco and using marijuana; (5) examination of multiple use patterns of two or more substances revealed that females most often used cigarettes and alcohol in combination, and males preferred a combination of marijuana and alcohol or marijuana and cigarettes; (6) ninth grade senior high school students smoked considerably more than ninth grade junior high school students; and (7) the most significant increase in alcohol and marijuana use was evidenced between seventh and eighth grades, and eighth and ninth grades respectively. Age-appropriate intervention programs may need to consider ethnicity, school environment, and substance-specific initiation points. Data are presented on five tables. A 6-item list of references is included. (BJV)