Background: HIV/AIDS is one of the leading causes of morbidity and mortality globally, especially in SSA. In Tanzania ~ 1.8 M adults PLWHA, 60% are women of reproductive age. HIV prevalence among pregnant women is also high in Tanzania, ranging from 3.5% to 18.2%, as a consequence of high rates of MTCT of HIV. As the reflection of this paediatric HIV increase infant morbidity and mortality. Therefore national PMTCT program was introduced in 2004, and in Morogoro Municipality it was scaled to all primary health care in 2008. For HIV positive pregnant women, self disclosure to their partners, shown to be vital for uptake and adherence to PMTCT & in HIV prevention and care. Self disclosure enables couples to engage in dialogue, prevention and access to early care. However, disclosure rates to partners have been shown to be low in developing countries (range 17-40%). Objectives: To determine the prevalence and predictors of HIV disclosure to partners among HIV positive pregnant women in Morogoro municipality. Methods: A cross section study was conducted among 250 HIV positive consenting pregnant women who were attending the antenatal clinics, in six randomly selected government primary health care facilities. They were interviewed using a questionnaire with closed and open-ended questions to get information on possible predictors of HIV disclosure to their partners. Data were entered and analysed using SPSS statistical package version 13. The statistical significance was considered when the p-value was ≤ 0.05. Results: Of the 250 enrolled women, their age ranged between 18 and 41 (mean, 27; SD: 5.3) years. Majority, were married/cohabiting (92.0%), had primary education (66.8%), were unemployed (78.8%), and were earning monthly income of < 100,000 Tanzanian Shillings (TZS) per month ~ (83.0%). The proportion of respondents disclosing HIV status to partners was 40.8%. Factors that were independently associated with HIV status disclosure to partners were gravida (p=0.005), diagnosis of HIV before current pregnancy (p<0.0001), discussion with partner before HIV testing (p<0.001), dependency on partner for food, house rent, school fees (p<0.001) and age difference between partners (p<0.003). Conclusions The study showed a relatively low proportion of HIV serostatus disclosure. Discussion before HIV testing, time since HIV diagnosed, socio-economic status of women, women’s age and gravida associated with disclosure of HIV serostatus