Purpose: The study sought to identify the differences in chronic diseases and physical activity in elderly women by BMI. Method: The subjects of this study were 644 elderly women 60-80-years-of-age living at home. The research instruments were physical activity levels and chronic diseases. Subjects were given a self-report questionnaire. Data were analyzed using the SPSS win program. Result: Hypertension, prevalence of diabetes mellitus and hyperlipemia were significantly different in the subjects according to body mass index, being higher in obese subjects than in non-obese subjects. Physical activity in each of the body mass index groups did not differ significantly. Conclusion: Obesity increases the risk of chronic diseases. This knowledge could help elderly women control their weight, reduce chronic diseases, and ultimately, gain better health.