Five fatal cases of Japanese patients with type 1 Gaucher disease were studied. The causes of death included hemorrhage secondary to esophageal varices (two cases), respiratory distress (one case), hepatic failure (one case) and postoperative sepsis (one case). All of the patients had previous splenectomies, four patients had bone involvement and hepatic cirrhosis. The identified Gaucher genotypes were 1448C/1213G, 1603T/1603T, 1448C/1390G, and 1213G/1213G. The prognosis of type 1 Gaucher disease is generally good. We propose that patients with a similar clinical course and genotype to those presented in the present study should receive prompt comprehensive treatment. Patients with the 1213G mutation, pulmonary and liver involvement and a previous splenectomy should be considered as candidates for early vigorous treatment.