Seven patients affected with visceral leishmaniasis have been tested for polymorphonuclear leukocyte functions and for presence of circulating immune complexes during the course of the disease and on recovery. These parameters have been correlated with clinical features; phagocytic and killing defects observed during acute stages of the disease seem to be dependent from high levels of circulating immune complexes observed in same period. Reduction of CIC levels observed after a first course of therapy are probably related to the gradual improvement of phagocytic functions which are almost complete in all patients at recovery.