BACKGROUND: Nowadays, grandparents have a major role in taking care of their grandchildren. Also, caring for grandchildren is a common and normative experience for many Iranian grandparents. The present study aimed to compare the quality of life of physically active and inactive grandmothers caring and non-caring for grandchildren.METHODS: This analytical cross-sectional study was conducted on 300 grandmothers at the age range of 50 to 70 years old, who lived in Bojnurd, northeastern Iran (2018). Data were collected using the questionnaires of 36-Item Short Form Health Survey (SF-36) and Baecke Physical Activity, and demographic information.RESULTS: The total scores of quality of life in caring physically active, physically inactive, non-caring physically active and noncaring physically inactive grandmothers were 76.95±6.33, 71.74±9.41, 75.56±5.9, and 56.06±11.23, respectively. There was a significant difference in the comparison of the quality of life score in caring grandmothers in two active and inactive groups (P<0.001). In addition, the quality of life score of non-caring grandmothers indicated a significant difference in physically active and inactive grandmothers (P<0.001).CONCLUSION: According to the results of this study, it seems that caring physically active grandmothers have higher quality of life. It can be suggested that the grandmothers who care for their grandchildren may improve their health and quality of life by incorporating the programs to increase physical activities in their daily life.