By age 35 there were no cumulative effects of the use of illicit drugs on wages. Specification of the relationships at various stages of the life cycle revealed that the effects of illicit drug use were positive in the early stages of labor force participation (by the late 20's) but negative in later stages (by the mid-30's). The negative impact of drug on earnings apparently took more than a decade to manifest itself and was reflected in lower rates of earnings growth. The authors propose that a labor market theory of life-cycle compensation contracts and investments in training and the differential impact that different types of job changes have in the short-run and the long-run among users and nonusers provide a partial accounting of the processes underlying the observed opposite relationships between drug use and earnings at different age periods. The importance of adopting a life-span perspective is highlighted by the findings. 3 figures, 3 tables, and 57 references