The following article describes five patients with plasma cell leukemia treated during the last two years at a Medical University Polyclinic. Plasma cell leukemia is a disease which was seen extremely rarely in the past. The disease can develop in patients with multiple myeloma or, even more rarely, as a "de novo" disease. Generally patients with plasma cell leukemia are younger than the multiple myeloma patients and have a higher incidence of organomegaly. Despite the fact that patients with plasma cell leukemia received the same intensive chemotherapy as those with multiple myeloma, their prognosis was considerably worse, with a median survival time of only five month.