Given the general poor state of health care and the devastating effect of user fee, the National Health Insurance Scheme (NHIS) was instituted as a health financing policy with the main purpose to ensure universal access for all Nigerians. However, since NHIS became operational in 2005, only members of scheme are able to access health care both in the public and in private sectors, representing about 3% of Nigerian population. The thesis therefore examines the design and implementation policy of NHIS in Oyo state, Nigeria. Key design issues conceptual framework guides the analysis of data. The framework identifies three health interrelated financing functions namely revenue collection, risk pooling and purchasing. Data was collected from the NHIS officials, employees of the Health Maintenance Organisations (HMOs) and the Health Care Providers (HCPs) using key informant interview. In addition, in-depth interview and semi structure questionnaire were used to gather data from the enrolees and the nonenrolees. Empirical findings show that NHIS is fragmented given the existence of several programmes. In addition, there is no risk pooling neither redistribution of funds in the scheme. Revenue generated through contributions from the enrolees was not sufficient to fund health care services received by the beneficiaries because of the small percentage of the Nigerian population that the scheme covers. Further findings indicate that enrolled federal civil servants have not commenced monthly contribution to the NHIS. They pay 10% as co-pay in every consultation while federal government as an employer subsidised by 90%. Majority (76.8%) of the respondents agreed that they were financially protected from catastrophic spending. However, the overall benefit package was rated moderate because of exclusion of some priority and essential health care needs. Although above half (57%) of the respondents concurred that HMOs are accessible, in the overall, (47.6%) of the respondents were not satisfied with their services. In the case of the HCPs, majority (61.9%) of the respondents claimed that there is no excessive waiting time for consultation. Furthermore, (64.3%) rated their interpersonal relationship with the HCPs to be good. However, more than half of the respondents (54%) disagreed on availability of prescribed drugs in NHIS accredited health facilities. For the nonenrolees, findings show that most of the respondents (72.9%) were willing to enrol, but significant proportion (47.5%) indicated financial constraint as impediment to enrolment. / Sociology / D. Phil. (Sociology)