The analysis used three approaches: (1) examining the trend in drug selling between 1983 and 1989; (2) assessing differences between sellers and nonsellers on demographic characteristics, levels of alcohol and drug use, and problems; and (3) drawing detailed profiles of drug seller types. Data came from the students aged 15 to 20 in grades 11 and 13 in the 1983, 1985, and 1989 waves of the Ontario Student Drug Use Survey. There were 2,037 youths in 1983, 2,008 youths in 1987, and 1,749 youths in 1989. Data from 1989 for the 67 self-reported drug sellers were compared with data from 86 randomly selected nonsellers. Results revealed that drug selling declined considerably between 1983 and 1989. Sellers were more likely to be males and to use alcohol and drugs more often than nonsellers. Sellers also had more alcohol and drug problems and engaged in more delinquent acts than did nonsellers. Drug sellers who sold marijuana only were less frequent users of drugs, less likely to have drug problems, and were also delinquent. Figure, table, and 15 references