BACKGROUND: This was a prospective case-control study that investigated the prevalence of antiphospholipid antibodies (aPL) in HIV-infected children. It also evaluated its association with patients’ clinical stage, features of autoimmunity and presence of cytopaenia. HIV-infected children studied were either on Highly-active antiretroviral therapy (HAART) or HAART-naïve; while apparently healthy age and sexmatched HIV-negative children served as controls. INVESTIGATIONS: Six milliliters of venous blood was collected from each consenting HIV-infected child and the HIV-negative controls. Out of this, 1ml was added to paediatric size vacuum K2 EDTA specimen bottle, 2.25ml added to 0.25ml 32g/L sodium citrate and the rest clotted for anticardiolipin antibody assay. Full blood count was done using the Sysmex KX-21N, CD4+ lymphocytes count was done using Cyflow Counter 1 machine, following both reagent and machine instructions. Direct Coombs’ tests (DCT) and activated partial thromboplastin time (aPTT) were carried out according to standard operating procedures (SOP). Kaolin clotting time (KCT) test and anticardiolipin antibody (aCL) assay were also performed according to SOP for subjects and controls with prolonged aPTT. These were done in subjects and controls.