In a 1990 Massachusetts-wide random digit-dial telephone survey of 16-19 year olds, 66% reported sexual intercourse of whom 64% had sex after drinking and 15% after other drug use. Thirty-seven percent always used condoms. Forty-nine percent were more likely to have sex if they and their partner had been drinking, and 17% used condoms less often after drinking. Fewer, 32%, said they would be more likely to have sex if they and their partner had used drugs, with 10% less likely to use condoms after drug use. Since so few adolescents consistently use condoms, the greatest risk for HIV, sexually transmitted diseases, and unwanted pregnancy is the increased likelihood of having sex after drinking or drug use, not the decreased likelihood of condom use after drinking and drug use.