Background: About 2.3 million children who are under 15 years old living with HIV/ AIDS in the world and the majority living in Sub Saharan Africa. Without any intervention it is estimated that 35% of the children born to HIV infected mothers will be infected with Virus. Preventive of mother to child transmission has been effective in most places, however, some barriers such as disclosure cause the program not to be effective. While disclosure of HIV by women attending PMTCT clinic has been an important intervention on prevention of HIV in couples and unborn children, however, disclosure in pregnant women is low estimated to be around 40% compared to the general populations where its about 80%. Therefore, determining predictors of HIV disclosure among pregnant and lactating women is important. Objectives: To determine the prevalence and factors associated with HIV disclosure among HIV infected pregnant and lactating women attending PMTCT in KCMC hospital, St. Joseph Designated Hospital, Majengo and Pasua Health centers. Methods: A cross sectional study will be conducted among 406 HIV positive consented pregnant and lactating women who will attend to the clinic during study in two different hospitals. They will be interviewed using a questionnaire with closed and open-ended questions to get information on possible factors of HIV disclosure to their partners. Data will be entered and analyzed using SPSS statistical package version 22. The statistical significance will be considered when the p-value was ≤ 0.05.