Devolution entails the transfer of certain powers and responsibilities and resources from the central government to popularly elected regional or local governments that are established by law. There has been a trend in the devolution of authority in healthcare whereby the authority that is often sitting with one central Ministry or Department of Health is devolved over time to the local government. The health sector in Kenya has faced numerous challenges such as poor management structures, inadequate staff and delayed staff salaries, which combined have often led to strikes and paralyzed delivery of health services and Nairobi City County is not any different. The objective of the study was to investigate the effects of devolved governance on service delivery in public health facilities in Nairobi City County, Kenya. It sought to: examine the quality of patient care in Nairobi City County public health facilities; examine the effects of devolving management of human resources for health to the counties on service delivery in public health facilities in Nairobi City County, Kenya; explore the effects of devolving infrastructure management to the counties on service delivery in public health facilities in Nairobi City County, Kenya; and establish the effects of devolving commodities management to the counties on public health facilities in Nairobi City County, Kenya. The researcher used a descriptive research design. The study target population was 3764 out-patients and health workers from two public health facilities in Nairobi City County, Mama Lucy and Mbagathi. The study sampled 362 out-patients and health workers. The sample size for the study was determined by a scientific formula (Israel, 1992). Primary data collection methods for this study was a questionnaire and interview schedules. Descriptive statistics were used to analyse data and correlation analysis was used to show the relationship between variables. The findings show a strong positive significant relationship between quality of patient care and service delivery with a correlation coefficient of 0.660. The study applied Spearman’s rho Rank Correlation to determine the relationship that existed between quality of patient care, devolved human resources management, devolved infrastructure management, devolved commodities management and service delivery. The study concluded that if all four variables are being managed efficiently and effectively, then the quality of health service delivery would improve significantly. The study recommends that the Nairobi City County Government allocates a higher percentage of the total County budget to health care. Key Words: Devolution, Healthcare, Infrastructure, Commodities, Patient Care, Service Delivery