Substance use patterns and predictors of substance use by women aged 65 and over were examined using data from the Canadian National Alcohol and Other Drugs Survey (1989). Use patterns were consistent with findings from previous surveys: that older women drink less alcohol, smoke less and use less illicit drugs than other age-gender groups. Also consistent with previous surveys, older women reported the highest rate of psychoactive prescription drug use of all groups. Bivariate analyses indicated significant relationships between some social and demographic variables and substance use. Drinking was associated with being single, younger, not religious, in better health, and smoking. Smoking was associated with being younger, not religious, in poorer health, having less social support, drinking, and use of psychoactive prescription drugs. Use of psychoactive prescription drugs (especially sleeping pills) tended to be associated with being widowed, older, less educated, more religious, in poorer health, experiencing higher stress, having lower income and less social support, smoking, and use of other psychoactive prescription drugs. When data were analysed using principal component analysis, two very consistent dimensions of substance use emerged for older women: greater religiosity associated with less drinking and smoking, and a dimension involving use of all types of psychoactive prescription drugs. These findings are discussed in terms of projected use patterns for future older women and the need for a better understanding of the social context of older women's substance use that involves light to moderate alcohol use but a higher rate of use of psychoactive prescription drugs than other age-gender groups.