Within high HIV prevalence settings, the integration of HIV and SRH services has been widely regarded as beneficial in not only improving individual outcomes and reducing HIV transmission, but also improving the efficiency of service delivery. However, while ample evidence exists on the behavioural, health and social outcomes, evidence on the economic benefits of integrating these services remains scarce which is a barrier to creating effective policy. This thesis therefore aimed to contribute to the understanding of the optimal organisation of HIV and SRH services in high and medium HIV prevalence settings. To achieve this aim, data was collected from 40 health facilities providing integrated HIV and SRH services in Kenya and Swaziland. Costs of providing these integrated services were estimated and the impacts of integration (among other organizational and contextual factors) on the technical and cost efficiency explored using non-parametric and parametric methods respectively. This thesis presents the first study to analyse both technical and cost efficiency in this context. It further extends the literature on efficiency measurement in low and middle income settings by considering two particularly relevant aspects of health care provision: quality of care and the impact of organisational and contextual factors on the technical efficiency of health facilities. The findings from this thesis are especially relevant to the on-going discussions of the optimal organisation of HIV and SRH services in resource constrained settings. These findings not only show that inefficiencies exist in the provision of integrated HIV and SRH services but underscore the importance of investigating both technical and cost efficiency as the results differ depending on the type of efficiency analysed.