Obesity usually is defined as the presence of and abnormally amount of adipose tissue. In many epidemiologic study, obesity as a health risk factor has been estimated by Body Mass Index(BMI) in general. This study was conducted to review of body fat percent measured by Bioelectric impedance analyzer as a estimator of obesity in a rural adult population. The study subjects were 421 men and 664 women who reside in the area on the Juam lake. They were sampled by multistage cluster sampling. Their mean age was 59 years old. Body fat percent increased with age, but BMI decreased with age in this study. Body fat percent was more larger at female and elder on the same BMI. The correlation coefficient between with body fat percent and body mass index was low (r=0.4737). Body fat percent was explained by not only BMI but also sex and age $(r^2=0.63)$. The result suggested that it is inadequate for BMI only to estimate obesity about elderly person who reside in the rural community. The relation of body fat percent and body mass index of this study agreed with the preceding know-ledges and studies in general.