The role of blood platelets in the pathogenesis of malaria remains unclear. In this study we investigated the role of experimentally caused thrombocytopaenia in chronic (Balb/C) and acute (CBA/J) Plαsmodium-berghei-induced murine malaria. A group of 30 Balb/C mice were rendered thrombocyto-paenic by injection of anti-mouse platelet serum given every 2 days from day 2 to day 8 after malaria infection. Compared with the control group, thrombocytopaenic mice showed a greater mortality. The Kaplan-Meier estimate of the risk of death was 4.37-fold higher in the thrombocytopaenic group. Parasitaemia and weight loss was in agreement with the protective effect of platelets. In the acute malaria model, the survival rate was less significant but the estimated risk of death was 1.7-fold higher in the treated group. These results suggesting a protective role of platelets in murine malaria are not in line with previous reports of the literature. Taken together our data suggest, however, that platelets, similarly to some inflammatory cytokines like TNF, play a dual role in the pathogenesis of malaria. Depending on experimental conditions, e.g. the time of onset of thrombocytopaenia, the beneficial role of platelets may outweigh the deleterious one.