Masters of Science / There is evidence of the rising incidence and prevalence of chronic diseases of lifestyle in developing countries. It is estimated that by 2020 chronic diseases of lifestyle in Sub-Saharan Africa will be almost 50% of the burden of disease. Rapid urbanization with changes in lifestyle, such as physical activity patterns could explain at least partially the ongoing epidemiological transition. The purpose of this study was to assess levels of participation in physical activity among working Rwandan women in Kigali, in relation to socio-economic demographic characteristics. A cross-sectional study design using both quantitative and qualitative methods was used. Participants' level of participation in physical activity and influence of socio-economic demographic factors on questionnaire adapted from Sub-Saharan African Questionnaire. A focus group discussion assessed the need for a health promotion program related to physical activity participation among working women. Data analysis, using Statistical analysis version 8e, was used to obtain frequency tables and histograms. Chisquare tests and Fisher's exact tests were utilized to test for association between variables. Focus group discussion data were transcribed and translated into English. Data were then coded and put into themes and categories. There were 352 participants, with a mean age of 33.4 years. 71.9% of the participants were classified as sedentary and only 28.1 % of the participants were classified as physically active. Participation in physical activity decreased with age, and there were more participants classified as sedentary people in the married group (77%) than in non-married group (63.2%). A lower level of education and income of participants, the higher the level of participation in physical activity. Among the reported prevalence of chronic diseases, high blood pressure and diabetes were only reported by participants classified as sedentary. During the focus group discussion, participants reported facilitators and benefits of physical activity including, routine, relaxation, socialization and fitness, managing obesity and health purposes. Barriers limiting the participants' ability to engage in physical activity included lack of time, lack of knowledge, laziness, domestic helper, lack of motivation and culture. The main themes, which were identified as important in the development of a health promotion program were: The education and encouragement of girl children; education of women in the community, finding facilities and appropriate venues, a suitable environment and the contribution of physical activity program towards unity and reconciliation was emphasised. The findings of this study demonstrate a problem concerning sedentary lifestyle among the working women in Kigali/Rwanda. It is alarming that the participants who are already classified as sedentary and who will probably experience the consequences of sedentary lifestyle in the future are already reporting chronic diseases like high blood pressure and diabetes. There is therefore an urgent need to design, implement and evaluate a health promotion intervention aimed at promoting a physically active lifestyle in Rwanda.