Urine screening for drugs is increasingly employed in the United States in an effort to reduce illegal drug use and its consequent morbidity, mortality and economic burden. The family physician may choose to ensure proper urine specimen collection or may choose to develop expertise as a medical review officer; training courses and materials are available. In addition, certification is available from several organizations. The physician who becomes a medical review officer is responsible for interpreting positive tests and may also become involved in drug rehabilitation programs. It is prudent to follow federal guidelines for occupational urine drug screening, even when these guidelines are not mandatory, to protect against a possible challenge to a positive specimen on the grounds of improper processing. In all cases, care should be taken to correctly identify the patient, to label all specimens and to document that the specimen has been secured against tampering.