HIV, HBV and syphilis in pregnancy are associated with adverse pregnancy outcomes including spontaneous abortion, preterm birth, still birth, low birth weight, congenital infections etc. Objectives: The present study was undertaken to know the seroprevalence of HIV, HBV and syphilis in and around bihar. Methods: The study was conducted in the Department of Microbiology, IGIMS, Patna. The study included 300 blood samples from antenatal women attending outpatient and inpatient and also private hospital antenatal cases, whose blood samples were sent for routine blood investigations to our Laboratory. All the test sera were tested for anti-HIV IgG antibodies by a DOT immunoassay, if reactive was confirmed by TRIDOT and ELISA test. They were also tested for HBV by HBsAg ELISA and syphilis by VDRL test, if reactive was confirmed by TPHA test.