Leucocyte esterase (LE) in first-voided urine (FVU) and presence of leucocytes in urethral and cervical smears were evaluated to identify Mycoplasma genitalium infection in 416 men and 417 women attending Department of Genitourinary Medicine. M. genitalium was diagnosed in FVU specimens by realtime polymerase chain reaction. The prevalence of M. genitalium was 6.5% in women and 6.7% in men. In total, 88.5% (23/26) of M. genitalium-infected men were identified by a combination of urethral smear and the LE test. In women, the combination of urethral and/or cervical smears and/or a positive LE test identified 91.3% (21/23) of M. genitalium-infected patients. Organism load in FVU correlated significantly with presence of urethritis (> or =4 leucocytes per high-power field) in men. A combination of LE testing of urine and urethral and/or cervical smears can be used as screening tests to select patients for specific M. genitalium testing. By this strategy, about 10% of infected individuals will remain undetected.