Purpose: To identify the effect of walking exercise on the body composition and physical fitness in obese college women. Method: The research design was a nonequivalent control group pretest posttest. Thirty-seven subjects were surveyed using a structured questionnaire, and measured for body composition and physical fitness. Twenty persons in the experimental group among the total sample participated in a 12-week walking program. The data were analyzed by $x^2$-test, and t-test with SPSS 10.1 program. Results: 1) BMI, body fat mass and percentage of body fat in body composition were significantly decreased in the experimental group compared to the control. However, there was no significant difference in skeletal muscle mass between the two groups. 2) Power among physical fitness was significantly increased in the experimental group. However, there was no significant difference in muscular strength (back strength), flexibility (sit and reach), muscular endurance (abdomen curl), power (standing high jump) or agility (trunk reaction time) between the two groups. Conclusion: The above results, confirmed the effectiveness of walking exercise as an effective nursing intervention in order to improve body composition.