Although there is much descriptive research concerning frequency of drug use, few studies have reported quantitative data on patterns of drug use. 33 college students with experience with a variety of drugs were studied. Alcohol and some legal drugs were included as well as drugs of abuse. Guttman scalogram analyses yielded very high coefficients of reproducibility (.89 to .98). The pattern of drug use was cross-validated on a sample of young drug users in another setting. The relative frequency of drug use for our sample was also highly related to that reported in other studies of student populations. In order to identify the dimension underlying the pattern of drug use, ratings of the safety and availability of each of the 18 substances were obtained. Both availability and safety were highly related to the relative frequency of drug use, with availability being the more important variable.