A report of 27 drug induced agranulocytosis is presented in a period of 13 years. The rate of the disease was 0.12% of the total number of patients. Cases due to cytostatical and radiation treatment were not included. According to bone-marrow cellularity patients were divided into hypo- and hyper-cellular groups. The clinical findings were similar in both groups and the majority of patients recovered. Two patients died, both in the hypocellular group: the first due to mycotic pulmonary infection, the other after massive pulmonary embolism but after complete haematological recovery. Bone-marrow plasmocytosis was slightly expressed in the hypocellular group. The normal leukocyte number appeared after treatment within 3-25 days. Recurrent agranulocytosis was observed in four patients and permanent leukopenia developed in five. The leukocyte-agglutination test was positive in 10 cases only, but the leukocyte migration test was positive in all investigated cases except two. Five patients had a previous history with idiosyncrasy. Treatment was started with antibiotics, corticosteroids and with antimycotic drugs. Sterile island and granulocyte-transfusion was applied in seriously ill patients with septicemic complications only.