Abstract The present study assessed patterns of multiple drug use among a sample of university employees and students who had been identified as having moderately high drug use habits. Use of eleven categories of legal and illegal drugs was tested and subjects reported how much of each drug they currently and habitually used. Factor analysis yielded three factors of drug use. Four of the items in the first factor (hallucinogens, cocaine, marijuana, alcohol) exhibited moderately strong and positive intercorrelations, suggesting that this particular pattern of drug use was the most common and/or reliable among young adult drug users. Sedatives and opiates were the highest loading items on the second factor, suggesting a pattern of drug use motivated by the desire for relaxation and stress avoidance. The third factor identified a pattern of legal stimulant use involving two of the three food-like categories of items employed in the present study (i.e., caffeinated cola beverages and chocolate, but not coffee). The results provided only mixed support for the hypothesis that categories of drugs with similar pharmacological properties define patterns of multiple drug use.