Background Integration of HIV treatment with other primary care services has been argued to potentially improve effectiveness, efficiency and equity. However, outside the field of reproductive health, there is limited empirical evidence regarding the scope or depth of integrated HIV programmes or their relative benefits. Moreover, the body of work describing operational models of integrated service-delivery in context remains thin. Between 2008 and 2011, the Lusaka District Health Management Team piloted and scaled-up a model of integrated HIV and general outpatient department (OPD) services in 12 primary health care clinics. This paper examines the effect of the integrated model on the organization of clinic services, and explores service providers' perceptions of the integrated model.Methods We used a mixed methods approach incorporating facility surveys and key informant interviews with clinic managers and district officials. On-site facility surveys were carried out in 12 integrated facilities to collect data on the scope of integrated services, and 15 semi-structured interviews were carried out with 12 clinic managers and three district officials to explore strengths and weaknesses of the model. Quantitative and qualitative data were triangulated to inform overall analysis.Findings Implementation of the integrated model substantially changed the organization of service delivery across a range of clinic systems. Organizational and managerial advantages were identified, including more efficient use of staff time and clinic space, improved teamwork and accountability, and more equitable delivery of care to HIV and non-HIV patients. However, integration did not solve ongoing human resource shortages or inadequate infrastructure, which limited the efficacy of the model and were perceived to undermine service delivery.Conclusion While resource and allocative efficiencies are associated with this model of integration, a more important finding was the model's demonstrated potential for strengthening organizational culture and staff relationships, in turn facilitating more collaborative and motivated service delivery in chronically under-resourced primary healthcare clinics. © 2012 The Author; all rights reserved.