Quartan malarial infection causes an immune complex nephritis in some individuals, which, once established, is sustained by mechanisms not yet fully explained, but which probably involve autoimmune processes. The presenting clinical and biochemical findings of the quartan malarial nephrotic syndrome are similar to those classically described for the nephrotic syndrome in childhood, but the renal pathology seen on light, electron, and immunofluorescent microscopy show striking differences and distinctive features. The disease tends to pursue a chronic course and in most patients is nonresponsive to treatment with antimalarial drugs, prednisolone, and immunosuppresive drugs. The overall prognosis is poor, with most patients developing hypertension and evidence of renal failure within 3 to 5 years of onset.