The drug use items were included in the military's Educational and Biographical Information Survey for military applicants during the spring of 1983. The research examined the criterion-related validity of preemployment drug use information. Results revealed that for all drugs examined, the greater the frequency of use and the earlier the age at which the drug was first used, the greater the probability of the person being classified as unsuitable after hire. However, the operational validity of each drug variable was influenced by the base rate of drug use. The low base rates for some drugs make their operational validity of limited value. The operational validity of the marijuana frequency of use measure (.07) was approximately equal to that of less frequently used drugs (e.g., stimulants and depressants). Findings did not indicate any strong moderators of the validity of a drug-composite measure. Tables and 33 references (Author abstract modified)