Urine screening for clinical diagnostic purposes is used to answer the question of whether adolescents are continuing drug abuse. The purpose of this study is to examine the use of urine screening as a procedure to assess and monitor adolescents in an outpatient program who are suspected of continued drug abuse. To systematically evaluate the procedure, 296 adolescent urine screens were analyzed. A total of 36% of the adolescents tested positive for one or more drugs of abuse, and 30% tested positive for cannabinoids (THC), with eight testing positive for other drug use. Among the total sample, five (2%) tested positive for opiates, and ten (3%) tested positive for multiple drug use. Of the total sample, twenty-seven (9%) had adulterated urine. In this study, urine screening, which was done for clinical purposes, appeared to be helpful in assessing continued drug use but provides little information regarding the diagnostic level and pattern of drug use.