Relationship between infections and human breast milk still requires more research especially, in developing countries. This study aims to evaluate the effects of HIV infection on immunologic factors in the breast milk and plasma of HIV infected lactating mothers. Plasma and breast milk concentrations of immunoglobulins G, A, M and E, caeruloplasmin (CLP), complement factor IIIc (C3c), α1-antitrypsin (A1AT), and transferring (TRF) were determined in 20 asymptomatic HIV-infected lactating mothers (HIM) and 30 age-matched HIV-free (seronegative) lactating mothers (HFM) using Enzyme Linked Immunosorbent Assay and Single Radial Immunodiffusion technique. The mean plasma level of IgM was significantly elevated in HIM compared with HFM while the mean plasma level of IgE was significantly low in HIM compared with HFM. The mean breast milk levels of IgA, IgM, CLP, C3c and TRF were significantly elevated in HIM compared with HFM. Significant positive correlation existed between IgE in the plasma and breast milk of HIM and plasma IgG had significant positive correlation with the milk IgG in HFM. Severe hypergammaglobulinaemia may not be a feature of Nigerian HIM and increased levels of CLP and TRF indicate low levels of Cu and Fe respectively in the breast milk of HIM.