The purpose of this study was to investigate the effects of bicycle exercise on physical fitness and blood components in the middle aged women. Twelve females were selected as subjects and then divided into two groups: the experimental group (n=5) and the control group (n=7). The experimental group were trained about 40 ㎞ per week and for 20 wks by bicycling. Both groups were tested by using the Astrand incremental cycle ergometer protocol. 2 ×3 ANOVA with repeated measure was performed for data analysis at the 0.05 level of significance. After a 20 wk period of bicycle training, VO₂max, total cycling time, and sargent pump in the experimental group were higher than control group (P＜0.05). However, no significant differences in flexion, grip and leg strength, lactate concentration and heart rate were shown, In terms of blood components, only hemoglobin and hematocrit were significantly higher in the experimental group (P＜0.05). In conclusion, even though there was no significant decrease in blood lipid profile after bicycle exercise, cycling has a beneficial effect on improving physical fitness level in the riddle aged women.