Introduction and Objective Primary health care (PHC) is the basic strategy towards national health development in Nigeria, and provision of its services has been devolved to the local government. However, the PHC system in Nigeria has been hampered by several factors which have produced a negative effect on quality. It is assumed that given the proper structure, quality medical care will follow. Hence this study seeks to assess the structure of PHC in a rural area of Lagos state, southwest Nigeria. Methodology The study was carried out in Ikosi-Ejinrin local council development area (LCDA) of Lagos state, which had 9 primary health care facilities catering for a population of about 100,000 people, using a descriptive cross-sectional study design. Data was collected from health facilities and health workers using a health facility checklist and a structured questionnaire for the health workers. Results Most facilities (77.8%) had inadequate water and power supply, as well as inadequate sanitary toilet facilities. In addition 44.4% lacked basic equipment and none had a maintenance plan. Ambulance service was available in only 11.1% of the facilities. Only 33% of the facilities could be accessed easily by public transportation. Stewardship was unsatisfactory as no facility had a regular work schedule for its workers, none had a copy of the Essential Drugs List, and only 22.2% of the facilities enjoyed community participation in planning and management. There were only 19 health care workers for the LCDA. There was neither a medical doctor nor community health officer, and the workers comprised nurses/midwives (57.9%), senior and junior community health extension workers (CHEWs)-21.1% and 15.8% respectively, and pharmacy technician (5.2%). None of the workers had gone on any in-service training within the previous two years. No health care workers knew anything about the budget for the health facilities. None of the facilities had a functional 2-way referral system in place. Only 22.2% had adequate size, layout, utilities and furnishings. Conclusion The structure of PHC Ikosi-Ejinrin LCDA, a rural area in south-west Nigeria, is inadequate. There is a need for increased political will, funding and intersectoral collaboration. Technical supervision, manpower management, community participation and 2-way referral system need to be improved upon. Keywords: Structure of primary health care, rural area, southwest Nigeria.