Homologous and heterologous malaria pathogens were used as antigens for the determination of malaria antibodies by indirect immunofluorescence. Homologous antibodies fell in the second half year, after successful treatment, down to the limit of demonstrability. In inhabitants of endemic malarial areas, who lived in the German Federal Republic, signs of a fall in antibodies could be observed after about 30 months. The predominance of particular malaria pathogens of the country of origin was recognizable in the antibody spectrum of these persons. Malaria antibody findings of three comparable groups of exposed persons under chemoprophylaxis ought to provide pointers to the parasitemias which had occurred and which were held responsible for the antibody production. Persons without chemoprophylaxis from malarial areas served as controls. The markedly deviating results of the antibody findings in the serum donors can only be explained by more seldom parasitemias in persons with adequate chemoprophylaxis.