Many companies go into CSR without proper feasibility study or plan and this usually affects the success and future sustainability of the projects. Corporate Social Responsibility is a core strategy in business as it enhances trust, reliance, respect and transparency. In the process of satisfying the needs of stakeholder groups, the companies are able to maximize their commitment to their investors who in turn benefit most. Many companies go into CSR without proper feasibility study or plan. This usually affects the success and future sustainability of the projects. This study sought to determine the critical success factors and sustainability of corporate social responsibility projects in cement manufacturing companies in Machakos County, Kenya. The study also sought to find out the influence of organizational culture, societal influence, environment impact and finance availability. This study adopted descriptive research design. The target population of the study was 588 respondents from the four selected companies. Stratified sampling was used to select 20 percent of staffs in the human resource department, therefore getting a sample size of 118. This study made use of primary data. The study collected primary data by use of questionnaires. Quantitative data was analyzed using Statistical Package for Social Sciences (SPSS) version 22. The descriptive statistics approach was adopted for analyzing and presenting the data in this research. This approach is important because it enables the researcher to meaningfully describe distribution of scores using statistical measures of central tendencies, dispersions, frequency distribution and percentages. Tables and figures were then used to present the analyzed data. In determining the relationship between dependent variable and four independent variables, a multivariate regression analysis was carried out. The study found a positive significant relationship between organizational culture, societal influence, political environment and finance availability on sustainability of CSR projects. The study concluded that involvement of local community enhances CSR project sustainability. Further, the study concluded that for successful implementation and sustainable project, necessary resources must be available. The study recommends that culture assessment should be done more often, probably on quarterly basis. Further, the study recommended that project beneficiaries must be consulted during project conception, preparation and implementation process. CSR projects are also recommended to be made autonomous devoid of any political interference.