Purpose: This study aimed to determine the effects of a 12-week metabolic syndrome BeHaS (Be Happy and Strong) program in elderly people with metabolic syndrome living alone, based on a community-based participatory research (CBPR). Methods: A nonequivalent control group pre-posttest design was used, and the participants were 43 elderly people living alone (experimental group 24, control group 19). The experimental group received a one-hour program per week and two individual health consultations during 12 weeks. The control group received two sessions about the metabolic syndrome and two individual health consultations. The effects of health behavior, blood pressure, blood sugar levels, abdominal circumference, triglycerides, and self-esteem were evaluated. The data were analyzed using the independent t-test and Mann-Whitney U test. Results: The health behavior with respect to the metabolic syndrome in the experimental group increased significantly (t = - 3.19, p = .002). Both diastolic blood pressure and abdominal circumference decreased in the experimental group (t = 2.00, p = .028 and t = 3.91, p < .001). No significant differences were observed between the groups in systolic blood pressure, fasting blood sugar levels, triglycerides, and self-esteem. Conclusion: The 12-week metabolic syndrome BeHaS program using community resources improves the health of elderly people with metabolic syndrome living alone. Based on these findings, further studies on the effectiveness of the metabolic syndrome BeHaS program and the experiences of those who participated in the CBPR are warranted.