This report is the result of a preliminary study of the demonstration of antigen-antibody complexes in the kidney of albino rats infected with Plasmodium berghei. Although the presence of parasites in the peripheral blood was demonstrated on the 2nd day of infection and the circulating antibodies on the 6th day by the fluorescent antibody technique, it was only on the 12th day that there were found deposits of antigen and antibody in the glomeruli and on the internai elastic lamina associated with a decrease of the levei of the hemolytic complement in the serum. On the 16th day the glomeruli presented a minimum deposit and the complement reached normal leveis. The author suggests that P. berghei can act as a pathogen to the host by means of formation of soluble antigen-antibody complexes. However, this subject needs additional study.