Objectives We aimed to investigate the effect of low and moderate intensity aerobic exercises on sleep quality of older adults. 
Methods & Materials The research method was quasi-experimental with pre-test and post-test design. The statistical sample included 45 volunteer elderly men aged 60-70 years who were divided randomly into two experimental groups (aerobic exercise with low and moderate intensity) and one control group. First, all subjects were evaluated by a proficient doctor to confirm their physical and mental health. Also, the maximum Heart Rate (HR) of subjects was obtained by subtracting one's age from 220. Furthermore, based on aerobic exercise type, the target maximum HR was calculated for each subject. The exercise protocol consisted of 8 weeks aerobic exercises (2 sessions per week) based on Rockport one-mile walking/running test. With using specific chest belts, the exercise intensity was evaluated and controlled. All subjects in pre-test and post-test stages were completed the Pittsburgh Sleep Quality Index (PSQI). 
Results In pre-test stage, results showed that there were no significant differences between control and experimental groups in sleep quality and its components (P>0.05). On the other hand, results in post-test stage showed that there were significant differences between control and experimental groups in this variable (P<0.05). Also, the Tukey Post Hoc test showed that the moderate intensity group scores in sleep quality and its components were better than other groups (P<0.05). Finally, the low intensity group scores were better than control group (P<0.05). 
Conclusion Generally, aerobic exercises with moderate intensity (60-70% max HR) had a positive and significant effect on sleep quality and its components. We recommend the aerobic exercises with moderate intensity as a useful medical treatment for improving sleep quality and its components among community older adults