Population aging has become an important social issue worldwide and the biggest challenge is improving older people's quality of life. We aimed to determine the quality of life (QOL) of retired older adults in Tehran using the SF-36. About 321 men and 146 women, aged 60 to 69 (62%) and 70 or older (38%), participated. In the older group, the total QOL score was lower than in the younger group, but the older group scored higher in the mental domain. Education had a significant relationship with the mental domain of QOL, as did gender with the physical and mental domains. The income sufficiency state was significantly related to both domains of QOL. The findings can be useful in designing intervention studies that could eventually lead to application of strategies to promote QOL in retired older adults in Iran and other countries with similar sociocultural and economic backgrounds.