The sample was randomly selected from boys enrolled in public schools in Pittsburgh, Pennsylvania. Smoking and alcohol consumption was surprisingly high even for first graders. The use of developmentally more advanced substances, such as marijuana, was associated with the use of substances that typically emerge earlier, such as beer. Significantly more of the multiple substance users in the first and fourth grade were already engaged in a variety of antisocial acts than were either single users or nonusers. The findings show that substance use, even at grade one and four, is an indicator of boys who commit a wide variety of antisocial acts. For the seventh graders, the use of marijuana was especially associated with the commission of more serious antisocial and delinquent acts. Multiple substance use reported by the seventh graders also signified a higher frequency and volume of use. 33 references, 5 tables, and appendix.