We have so far reported that atomic bomb (A-bomb) survivors have persistent subclinical inflammation. This study reports on the analysis of persistent inflammation among A-bomb survivors with respect to sex and age at the time of the bombings. Among 6258 A-bomb survivors undergoing seven inflammatory tests, standardized inflammatory scores, used as inflammation indices for each person, were regressed for city, age at examination, age at the time of the bombings, inflammatory diseases, smoking, and radiation dose, in order to analyze the effects of radiation dose. The results indicate that the inflammation scores increased significantly for both males and females younger than 20 years old at the time of bombings, while the scores increased significantly only for the females that were 20 years old or older at the time of the bombings. As evidence has been observed, on the one hand in the radiosensitive young generation, and on the other hand in the population with a high risk of radiation-induced disorders in the estrogen receptor organs, such as thyroid cancer, breast cancer, ovarian cancer and uterine myoma, a close association between the persistent inflammation and the radiation damage mechanism(s) is suggested.