The purpose of this study was to test the effect of keeping daily activity records on physical activity levels and self-efficacy for physical activity in adults with type 2 diabetes, and to examine the feasibility and acceptability of this intervention from the perspective of the participants. This intervention study included 58 individuals with type 2 diabetes aged 40 to 65 years. Participants were randomly assigned: individuals in the intervention group kept daily activity records for 6 weeks, mailed to the researcher every 2 weeks. Data collection was completed at the beginning of the study and 6 weeks later, using the habitual physical activity index and the self-efficacy for exercise scale. Participants in the intervention group also completed the perceived feasibility checklist. The intervention resulted in enhanced self-efficacy. Physical activity improved in both the intervention and control groups. Activity recording was judged to be acceptable and feasible. Daily activity recording can be used as part of a program to increase physical activity self-efficacy levels. Focused interactions between health care providers and patients may be enough to motivate people to higher levels of physical activity. The relationship between self-efficacy and behavior is complex and should be the subject of further research.