Background: Globally 499 million new episodes of curable STIs occur in the age group of 15-49 years, 80% in developing countries and 79 million in India alone. There is an increasing trend for viral STIs while bacterial STIs are on decline. Number of pregnant women with STIs is increasing by about 250 million a year in developed world and double that number in developing countries. The objective of the study was to estimate seroprevalence of STIs (Hepatitis C, Hepatitis B, HIV and Syphilis) and to evaluate impact of sociodemographic profile and sexual behaviour on STIsMethods: This observational study was carried out on 1000 asymptomatic pregnant females attending antenatal clinics, Department of Obstetrics and Gynecology, Government Medical College Patiala, Punjab.Results: Seroprevalence for STIs in asymptomatic pregnant females was 22.5%. Hepatitis C-9%, Hepatitis B-6.3%, HIV-5.5%, and Syphilis 1.7%. Illiteracy, low socio economic status, homemakers, rural background with multiple sex partners in the 21-30 years age group is associated with increasing trends of STIs in pregnancy.Conclusions: Screening asymptomatic pregnant women for STIs remains a key programme strategy for quadruple (Hepatitis C, Hepatitis B, HIV and Syphilis) prevention. Mandatory screening for STIs to reduce perinatal transmission is need of the millennium– a step toward ending STI epidemics as a global priority.