Background: Equitable access to primary healthcare is essential for public health, yet utilization of urban health centers remains suboptimal in some areas. This study explored factors influencing eligible individuals’ use or non-use of health centers in Taybad, Iran. Methods: A qualitative design with thematic content analysis was used. Participants were purposefully selected adults who had not visited urban health centers between November and March 2024. Data were collected through semi-structured interviews and analyzed by coding, categorization, and theme development. Results: Four main themes emerged: (1) structural and organizational barriers (e.g., inadequate infrastructure, crowding, workforce instability, lack of privacy); (2) service limitations (e.g., limited specialized care, insufficient quality, need for home-based care); (3) individual attitudes and behaviors (e.g., low priority of preventive care, lack of motivation, time constraints, personal reasons); and (4) follow-up and preference-related barriers (e.g., lack of active follow-up, preference for other centers). These factors affected access, quality, and acceptance of services. Conclusion: Non-utilization of urban health centers results from structural, service-related, and individual barriers. Improving utilization requires infrastructure enhancement, service expansion, workforce stabilization, and community education, with services designed based on real population experiences.