The high incidence of glomerulonephritis in East Africa has been reported by several workers. Most of these studies associate the prevalence of glomerulonephritis with Plasmodium malariae infections. Although it appears that the causal agent is in the local environment, and most likely to be an infection, there are many other parasites more prevalent in the area than Plasmodium malariae. The present work is based on a study on 175 Kenyan renal patients of which 70 were biopsied. Special emphasis wa s given to parasitic infections with Schistosoma mansoni , Plasmodium malariae, Plasmodium falciparum, Leishmania donovani, filariasis, ascaris and hydatidosis. Antibodies in the serum of the patients were detected by crossed (Immunoelectrophoresis against prepared parasitic antigens. Composition of circulating immune complexes and the complement profile of the patients was analysed. Hepatitis B viral antigen, anti-streptolysin 0 titre and total IgE of some of the patients was also determined. An enzyme immunoassay technique was developed to study the antigens in circulating complexes. Antisera against Schistosoma mansoni eggs and worms and Ascaris suum were raised in rabbits. The antibodies were labelled with peroxidase and used for the enzyme immunoassay. Serum from acutely infected patients was used in place of antiserum in the cases where antigens could not be obtained to immunise rabbits. The enzyme immunoassay technique mentioned above was used to study the cross reaction between the antibodies of patients with the circulating complexes of other patients, using peroxidase-labelled globulins to react with the complexed antigens in their own serum and that of other patients. The association between infections and glomerulonephritis for all the parasites was analysed. The results in the Kenyan patients have been compared with glomerulonephritis in the patients studied in London, largely of European origin, and not resident in East Africa. Analyses of the results show that because of the overlap in parasitic infections, no single parasite studied could cause all of the common type of glomerulonephritis in the area.