The objective of this study was to find out the effects of public participation in the implementation of successful health projects in Nyeri South sub–County. The study focused on the project cycles from identification, designing, execution, monitoring and evaluation. It sought to answer the following questions: To what extent does public participation influence project identification of public health projects? What is the relationship between public participation and project planning of public health projects? How does public participation influence designing of public health projects among residents? To what extent does public participation influence monitoring and evaluation of public health projects? To answer these questions the study used a descriptive study design using open and close-ended questions from the local community and interview among county staff. The study was guided by Social Capital Theory and Theory Of Change. Sampling of respondents was done through random sampling for fair representation while stratified sampling of health facilities was employed. In addition, key informants from four county wards were carefully selected. The area of study has a population of 87,373 according to the Kenya National Census, 1999. The researcher targeted a sample of 100 respondents. Data was cleaned, stored, coded, and analyseanalysed using both descriptive and inferential statistics and results presented in the form of tables, graphs, and charts, to explain the relationship between public participation and successful project implementation. Reliability and validity of the study was ensured through correct study questions and relevant methodology in data collection and interpretation. The result showed that since the calculated value of chi square was greater than the table value of chi-square in all the four hypotheses, all the null hypothesis were rejected and all four alternate hypotheses were accepted. The conclusion was that, public participation influences project identification, project planning, project design, and project monitoring and evaluation for successful implementation of public funded health projects in Nyeri South sub-County. The study recommends that community must be involved in all four stages of any public project to ensure that they meet their objectives and at the same time are accepted by the target community. Key terms: Public Participation, Successful Implementation, Public Health Projects