Client satisfaction with health service provision within the health insurance schemes are crucial to guide policy and decision making. Further on, the achievement of universal health coverage within the health insurance scheme in Nigeria requires evaluating the extent to which the expectations of those who have utilized health-care services, are met. This study was designed to assess NHIS-enrollees' satisfaction and the responsiveness of outpatient health care services provided under the NHIS at UNTH, Enugu. This cross sectional descriptive study was carried out between July and September 2018. Data on enrollee's satisfaction was collected using the standardized Patient Satisfaction Questionnaire, and data on responsiveness was collected using the questionnaire from a responsiveness survey designed by the WHO. The results show that of the 368 NHIS-enrollees in the survey, 269 (73.1%) were satisfied with the services they received and 190 (51.6%) respondents considered the services to be responsive to their needs, with 'choice of provider' and 'autonomy' ranking the least in domain of service. The factors independently associated with dissatisfaction with the NHIS services at UNTH (at p<0.05) include: having a family size of ≤4, having worked for 10-19 years in the civil service, and having >4 dependents. The factors independently associated were: male gender, rural residence, having attended the UNTH twice or thrice, and having worked in the civil service for <10 years or for 10-20 years. This study concludes that a high proportion of NHIS-enrollees were satisfied with outpatient services within the NHIS; however, NHIS outpatient services were responsive to the needs of only half of the enrollees. It is recommended that poorly performing domains of services are strengthened, especially 'choice of provider' and 'autonomy'; and that factors associated with non-satisfaction and non-responsiveness of outpatient services offered within the NHIS be addressed by orientation, training and local policy solutions.