Introduction: HIV/AIDS and Syphilis are among important public health problems that contribute to the maternal mortality facing most of pregnant women globally and especially in developing countries. Acquired immune deficiency syndrome (AIDS) is caused by the human immunodeficiency virus (HIV). HIV weakens the immune system, making the body susceptible to secondary infections and opportunistic diseases. Without treatment, HIV infection leads to AIDS, which is invariably fatal. (TDHS, 2010). Sexually transmitted infections (STIs) are a serious public health problem in developing countries. Syphilis is STIs caused by the spirochete Treponema pallidum and constitutes a major public health problem worldwide. Pregnant women are sexually active and at risk of sexually transmitted disease, including syphilis. Syphilis remains a major cause of reproductive morbidity and poor pregnancy outcomes in developing countries. Objective: The study aims to ASSESS HIV AND SYPHILIS SEROPREVALENCE AMONG PREGNAT WOMEN ATTENDING MAJENGO MUNICIPAL ANTENATAL CLINIC IN JUNE 2016. Methodology: A descriptive hospital based cross-sectional study was conducted at the majengo municipal antenatal clinic. Data was collected for one month (May 2016). All pregnant women meeting my inclusion criteria were enrolled in my study. Study population: All pregnant women attending the clinic and have agreed to my oral consent Results: The number of women involved in the study was 160, 9.4% were infected with HIV and 1.9% tested positive for syphilis and 9.4% had unknown results for syphilis. Amongst all age groups the ages 21-25 and 26-30 had the highest frequency 33.3%. HIV sero-prevalence was highest in secondary and primary 53.3% and 33.3& respectively, these results were statistically significant. HIV sero-prevalence was also higher among married women 73.3%. Syphilis was prevalent on the age group 20-25 66.7%, and also higher among the primary educated women 66.7%, it was also higher among the married women 66.7%. there was a 0.6% co-infection of syphilis and HIV. Conclusion: Most of these results were not statistically significant except for level of education on both HIV and syphilis sero-prevalence.