The purpose of this study was to assess organizational culture on performance in healthcare sector in Kenya. The study was guided by these objectives: To assess the impact of clan culture on performance of Kalimoni mission hospital Juja; To examine the effect of market culture on performance of Kalimoni mission hospital Juja; To establish the influence of adhocracy culture on performance of Kalimoni mission hospital Juja; To investigate the consequences of hierarchy culture on performance of Kalimoni mission hospital Juja.The study was anchored on Schein’s theory and the social learning theory. The study used descriptive survey design and used questionnaires to collect data from a sample of 35 staff. The study established that clan culture improves performance of the Kalimoni Mission Hospital through teamwork, shared values, beliefs and norms as well as respect and value for employees, mutual support among employees and promotion of open communication and sharing of information. Adhocracy culture is instrumental in improving performance of the hospital through promotion of employees’ initiatives, staff development, rewards, innovative thinking as well as originality. Hierarchical culture improves performance in the hospital through efficient service delivery, careful monitoring of performance as well as observing security of tenure, respect and compliance with policies of the hospital. The study recommends that the hospital management should have in place a reward policy for those who perform exemplary well, it should have a training policy to guide staff development, include the staff in decision making; encourage open communication; ensure that there are adequate resources to support hospital operations and should automate their services to enhance service delivery