Background: For adequate planning of healthcare services, a good knowledge of the burden and pattern of morbidity and mortality in the community is a key requirement. This study aimed at describing the morbidity pattern among patients at a National Health Insurance Scheme (NHIS) clinic in Southwestern Nigeria.Method: This was a cross-sectional study. Secondary data was extracted from case notes of 5,108 patients who visited the NHIS Clinic in a tertiary health facility in Southwestern Nigeria, from 2014 to 2018, using the International Classification of Primary Care (ICPC-2) to categorize the diseases. Data analysis was done using IBM SPSS Statistics for Windows, Version 25.0 (Released 2018; IBM Corp., Armonk, NY, USA).Result: Females were 2,741 (53.7%), males were 2367 (46.3%), and the mean age was 36.7±9.5 years. General and unspecified diseases were the commonest presentations. Malaria (1,268; 45.5%) was the commonest disease among the patients. Sex and age were associated with disease distribution (p-value = 0.001).Conclusion: Public health preventive strategies and measures should be undertaken to address the priority diseases as shown in this study.