To determine if urinary tract infection, high blood pressure and gestational diabetes mellitus (GDM) are underdiagnosed when prenatal urine testing is done on a clinically indicated vs. routine basis.Prenatal and delivery records of 2,981 subjects were reviewed in a predominantly Hispanic and medically underserved population. Patients prior to August 2002 received routine urine screening. After August 2002, women were tested only if preestablished criteria were present.The number of patients diagnosed with high blood pressure and urinary tract infection was equivalent in the 2 groups. Despite unchanged screening for GDM between groups, the incidence of GDM declined from 9.3% to 4.2%.GDM, high blood pressure and urinary tract infection will not be underdiagnosed if prenatal urine testing is done on an indicated basis. It is safe to discontinue routine urine screening when a regimen of initial urine cultures, GDM screening at 24-28 weeks, indicated urine chemical reagent strip testing and routine blood pressure determination is used. Criteria for indicated urine testing should be clearly defined and consistently followed by all staff.