A global review of the porblem of malaria accidentally transmitted by blood transfusion is reported in France during these ten last years. Biological and epidemiological studies of malariae are recorded. Among the factors involved in the transmission of malariae by blood transfuction, the persistence of the parasites in the donors is very important. It is often longer than usual in the subjects who have lived in endemic malarious areas for many years or are always travelling in these countries, because they are partly protected by their acquired immunity and may be carriers of asymptomatic infection. The viability of parasites in stored blood, red cells and preparations with platelets, leucocytes or plasma containing a few red cells with parasites is discussed. The prevention depended on the elimination of any blood donor who has ever had malaria appears to be the simplest method but it is also the most failible. The screening of donors by direct microscopy is obviously impracticable because of low density and often submicroscopic level of their parasitoemia. Screening donors by IFA test is the best method. If IFA test is negative four months after coming back from endemic areas and two months after ending suppressive therapeutic, whole blood, red cells, leucocytes, platelets and fresh plasma can be used on condition that the stay of donors in endemic areas had been not too long. If the stay in these countries was very long, blood will be only used for preparing lyophilized plasma, fibrinogen immunoglobulins or albumin.