Title VII has been interpreted by the courts to mean that employer decisions cannot be based on tests or procedures that adversely impact certain classes of employees in a manner not related to their ability to perform the jobs at issue in a safe and effective manner. Employers' probable cause drug testing of employees generally withstands the scrutiny of Title VII, because drug testing is only used when an employee's job performance falls below specified standards of safety and quality. The application of the testing is thus directly related to job performance. In the case of mandatory testing, however, discrimination may be charged if there is a disproportionality between general labor force demographics and drug user demographics. In using mandatory drug testing, therefore, employers must be prepared to show that drug use per se renders an employee unfit to perform assigned job functions safely and effectively. Random drug testing compounds the potential discrimination problem, because differential treatment may accompany the random selection of employees to be tested. Given the task of discrimination in employee drug testing, employers should continually monitor the potential discriminatory impact of employment decisions based on drug-test results, with attention to clarity of policy, consistency of implementation, and completeness of documentation. 18 footnotes.