In 1965, mail survey on environmental and individual factors was performed for 11,724 male a-bomb survivors, with the age of 40 to 69, selected from the group subjected to joint JNIH-ABCC investigation of life span in a-bomb survivors. During 10 years after the mail survey, 2,834 died. The aim of this mail survey was to clarify the relationship between the mortality and specific environmental, social, and economic factors. There was a relationship between high mortality and low social and economical condition for all causes of death combined, cerebral vascular diseases, all malignant neoplasms, and gastric cancer. Smoking was a significant risk factor to all causes of death combined, ischemic heart diseases, all malignant neoplasms, gastric, tracheal, bronchial, and lung cancers. The mortality due to cardiovascular diseases was significantly higher in a-bomb survivors with heavy weight. The mortality due to all causes of death combined, all malignant neoplasms, lung, and gastric cancer tended to become higher in a-bomb survivors who got married early.