The purpose of this study was to examine the effects of an exercise intervention for older married couples on exercise adherence and physical fitness. Thirty-six older married couples and 61 older adults participated in the study as couple and non-couple groups (CG, NCG, respectively). Participants attended an exercise class once a week and performed a home-based exercise program consisting of walking and strength exercise over eight weeks. Exercise adherence was assessed by the rate of non-absentee, walking habits (≥ 2 times/week), and strength exercise habits (≥ 6 items*2 sets/week). Physical fitness was assessed by the Senior Fitness Tests. Logistic regression analyses were conducted to obtain the CG’s odds ratios (ORs) and 95% confidence interval (CI) for non-absentee, walking habits, and strength exercise habits (reference: NCG). Analyses of covariance were used to examine the statistical difference in the degree of change (⊿) for physical fitness between CG and NCG. CG had significantly higher ORs for non-absentee and walking habits compared with NCG but there was no significant difference in the rate of strength exercise habits between the two groups. In regards to ⊿ for physical fitness, significantly higher ⊿ for upper extremity strength was observed in CG than in NCG, while there were no significant differences in ⊿ for other physical fitness items between the two groups. These results suggest that an exercise intervention for older married couples would be more useful to maintain higher participation in exercise program and walking and improving upper extremity strength.