This study compared leukocyte esterase dipsticks (LED) and endocervical Gram stains (EGS) as surrogates for culture diagnosis of gonococcal and chlamydial cervicitis in 495 STD clinic patients. Overall, gonorrhea prevalence was 15.7%; chlamydia prevalence (in the subgroup that was tested) was 17.8%. In diagnosing gonorrhea, LED and EGS performed similarly, with sensitivities of 68% and 76%, respectively, and identical specificities of 44%. In diagnosing gonococcal or chlamydial cervicitis, LED and EGS sensitivities fell to 48% and 47%, respectively, whereas specificities increased to 55% and 75%. These data suggest that, although both tests are imperfect surrogates for gonococcal and chlamydial culture, LED sacrifices little in sensitivity compared with EGS. Because LED does not require ancillary supplies, equipment, electricity, or trained personnel, its use may be feasible when Gram-stain diagnosis is impossible. Modifications of LED technology and specimen preparation should be sought to improve LED performance.