A 55 year old Liberian male was splenectomized after an abdominal trauma. A few days after splenectomy he experienced a pure Plasmodium malariae infection with high fever. He was later followed for 12 months with monthly blood films and temperature measurements, and did never show any signs of clinical malaria. The parasite densities observed during the longitudinal follow after splenectomy did not differ from parasite densities in villagers with intact spleens.