The Japanese Pathological Society has established a unique registration system for autopsy cases since 1958. The autopsy data are published every year as an annual which numbers 22 volumes and includes 443,604 cases. This annual entitled Annual of Pathological Autopsy Cases in Japan is composed of 2 parts. One is the description part in which autopsy records of individual cases (institution, autopsy number, age, sex, address, occupation, clinics, clinical diagnosis, pathological diagnosis, and remarks) are summarized in a formula with 108 Japanese characters. The other is the statistical part in which disease-specific frequency with age distribution, combination of multiple malignancies are recorded. For this statistical study, computerization of the autopsy data was started from 1974. Modified MOTNAC codes are used for malignant neoplasms and modified ICD codes for the other diseases. Computerization of autopsy data has led to accurate statistical studies of autopsy cases in Japan and will contribute to the development of medical science.