Cardiovascular disease is the leading killer of women in the United States today (American Heart Association, 2002). One of the major risk factors for the development of cardiovascular disease is obesity. According to the CDC (2001), 56% of women in the United States are considered either overweight or obese. Further, the prevalence of physical inactivity are more prevalent among women than men (Wen et al., 2002). The purpose of the study was to determine the relationship between physical activity levels and body mass index(BMI) in females. The participants were 23 females, aged 10-11(M=10.35±.56 yrs), 68 females, aged 18-25 years(M=22.05±5.5 yrs), and 57 females, aged 51-84 years(M=69.05±11.98 yrs). Data were collected at multiple health centers in a mid-western metropolitan community. Height was determined with a stadiometer and weight was measured with a balance beam scale. Blood pressure was measured with a calibrated sphygmomanometer. Physical activity levels for 10-11 year olds were assessed using the Modifiable Activity Questionnaire for Adolescents (Aaron et al., 1995) and for the 18-25 year olds, and the 51-84 year olds with the Lipid Research Clinics Physical Activity Questionnare (Ainsworth et al., 1993). A Pearson Product Moment Correlation was used to determine the relationship between BMI and physical activity levels. There was a significant correlation (-.702, p=.01 for BMI(M=18.12±4.62) and physical activity levels(M=2.46±1.17 days/wk) for the 10-11 year olds. There was a significant correlation(-.321, p=.04) for BMI(M=23.7±4.62) and physical activity levels(M=1.30±1.49 days/wk) for the 18-25 year olds. There was not a significant correlation(.325) for BMI(M=29.45±7.44) and physical acitivy levels(M=1.59±0.50 days/wk) for 51-84 year olds. In two of the three age groups the BMI was consistently correlated with activity. The higher the physical acitivity level, the lower the BMI. Youth and young women are at critical time in their lives in the development of healthy physical activity and appropriate BMI. Their current health status may have significant long term effects on their future health status. Health teaching, in the areas of physical activity and dietary habits, should be inplemented into educational opportunities. This study was supported by Southern Illinois University Edwardsville Multidisciplinary Grant Program.