Although long-term home oxygen therapy (LTOT) certainly prolongs survival, it is not known whether this advantageous effect is similar for both sexes. In this study, we analyzed sex-related differences in survival based on a very large population that had received LTOT from 1986 to 1993. A total of 9,759 patients with chronic obstructive pulmonary disease (COPD), sequelae of tuberculosis (TBsq), and chronic interstitial pneumonia (IP) were selected in 1,212 medical institutions for analysis of survival rates. The survival rates of both sexes were compared with each other using the Cutler-Ederer Method. Despite higher PaCO2 at the beginning, the survival rate of women was significantly better than that of men in these three disease categories. Cox's proportional hazards analysis further confirmed the gender effect on survival by eliminating the effects of age, PaO2, PaCO2, %VC, and FEV1/FVC. The mean survival periods of the women who died during follow-up periods were also significantly longer than those of men (0.41 yr in COPD, 1.84 yr in TBsq, and 0.78 yr in IP). From these findings, we conclude women have a better prognosis than men when they start receiving LTOT, regardless of the cause of respiratory failure.