All employees hired over a six-month period at a large hospital underwent pre-employment urinary toxicology screening. Results of the screening were kept confidential. After a year of employment, the personnel folders of all employees studied were reviewed. Twenty-two of 180 employees (12%) had tested positive for drug use. Employees in clerical/aide positions were significantly more likely to test positive than were employees in professional positions (17% vs. 6%). Drug-positive employees were also more likely to be young and male. Comparison of job performance variables, job retention, supervisor evaluations, and reasons for termination showed no difference between drug-positive and drug-negative employees. Eleven drug-negative employees were fired during the study; no drug-positive employee was fired. There was a strongly significant difference between clerical and professional employees on each of these variables. This study did not find a relation between drug use and job performance. The widespread use of drug screening prior to employment makes further studies of this issue important.