Background: Prospective analysis of 500 cases of vaginal discharge in tertiary health centre of Punjab. Objective: To study the prevalence of Sexually transmitted infections (STIs) in 500 outpatient of 15 -49 years age group with vaginal discharge and to evaluate the various factors influencing pattern of STIs. Method: All cases were subjected to cervical cytology, HIV ELISA, rapid plasma reagen (RPR) test for syphilis and Gram's staining, Giemsa staining and wet mount study of vaginal discharge. Results: Prevalence of STIs was found to be 58% and majority of infection was caused by G. vaginalis, Candida and Trichomonas. Pap smear showed koilocytosis in 5.6%, mild dysplasia in 1.8% and carcinoma cervix in 1.2% cases. Conclusion: Vaginal discharge is a common gynaecological complaint and STIs are significant cause of vaginal discharge.