Purpose: The purpose of this study was to examine the impact of internal corporate social responsibility on employee’s performance in Nigeria National Petroleum Corporation.Methodology: This study was descriptive, to satisfy the objective of the study two hypotheses were formulated. Sample for the study was 301 staff of NNPC. The methodology involved the use of simple random sampling and proportionate stratified sampling techniques. Data was gathered through the questionnaire and secondary sources. The data was presented using simple percentage and tables, while the hypotheses was tested using the chi–square statistical tool.  Findings: The findings reveal that the provision of healthcare services have significantly reduced employees’ absenteeism and training of employees has led to employees’ effectiveness in NNPC.Unique Contribution to policy and Practice: The study recommended that organizations should prioritize their social responsibilities to the staff by evolving plans and programmes that are staff oriented. Training of staff should be done constantly to sharpen their knowledge on the job task and that Organizations should evolve policies that allow for periodic health check and evaluation of the staff. The study showed that internal corporate social responsibility is essential in encouraging employee’s performance.