The aim of this study is to explore diverse characteristics of females aged 25 to 49 years grouped according to Body Mass Index(BMI), and to investigate the effect of body satisfaction and self-esteem on involvement in dieting within each BMI group. In total, 549 females who participated in an online survey were divided into groups based on BMI(underweight, normal, and overweight). Results demonstrated three key factors, as follows. First, differences were identified among BMI groups according to demographic characteristics(age, household income, and marital status), although no difference according to education level was found. Second, differences according to BMI groups were found in body satisfaction and involvement in dieting, whereas were not found in self-esteem. Third, model testing for each BMI group showed, a positive correlation between body satisfaction and self-esteem in all three groups. However, there was a difference in causal relationships among variable across BMI groups. Body satisfaction negatively affected and self-esteem positively affected involvement in dieting for the underweight and normal groups, whereas there was no causal relationship between variables in the overweight group. Based on these results, basic information of groups segmented by the level of BMI was obtained, which could be used for both academic and practical implications.