Background. The HIV epidemic in South Africa (SA) has had a substantial impact on laboratory services, at least partially owing to the well-described propensity to cytopenias in HIV-positive patients. Objectives. (i) To formally gauge the impact of HIV infection on the state sector haematology services in SA by determining the HIV seropositivity rate among full blood counts (FBCs) performed at a large academic state sector laboratory; and (ii) to document the prevalence of cytopenias among HIV-positive patients in this setting. Methods. Randomly selected FBCs submitted to the National Health Laboratory Service laboratory at Chris Hani Baragwanath Academic Hospital, Johannesburg, were extracted from the laboratory information system (LIS) and retrospectively reviewed. HIV test results and other pertinent information in the LIS were documented, as was the presence of any cytopenias. Results. HIV status was documented in 561 of 1 006 samples (55.8%), with 307 (54.7%) of these being HIV-positive. Of the HIV-positive patients, 63.2% had one or more cytopenia/s. Anaemia was present in 183/307 (59.6%) of the HIV-positive patients, and was severe (haemoglobin <8 g/dL) in 32/307 (10.4%). Multivariate linear regression analysis showed significant independent associations between the presence of anaemia and both immunological AIDS (iAIDS) (p<0.0001) and male sex (p<0.025), but not HIV viral load (VL) (p=0.33) or antiretroviral therapy (ART) exposure (p=0.70). Thrombocytopenia and neutropenia were present in 37/307 (12.1%) and 11/51 (21.6%) of the HIV-positive patients, respectively, with no statistically significant association between either of these cytopenias and iAIDS, exposure to ART or VL. Conclusions. The findings reflect the substantial impact of the HIV epidemic on state sector laboratory resources, particularly the haematology service.