This prospective study of female prison inmates assessed the effects of prison labour life style on the blood pressure (BP), serum lipids, and body mass index of pre- and postmenopausal female prisoners. This study was carried out in the largest women's prison, located in a town in the North East of Japan. The prison serves a reasonably large community. Three hundred and twelve premenopausal female prisoners and 88 postmenopausal female prisoners in a women's prison participated in this study. Weight and height were measured to calculate the body mass index, and systolic and diastolic blood pressure were measured with a sphygmomanometer. Serum samples were collected for serum lipid estimations. Base-line data of two groups were compared by unpaired t-test, and changes in these data from the initial values were tested by paired t-test. From our limited data, both the pre- and postmenopausal female prisoners showed decreases in systolic and diastolic pressure, total cholesterol, triglycerides, LDL-cholesterol, and body mass index. Both also showed increases in HDL-cholesterol. Given that almost all the women in this prison had the same labour life style, the findings of this study suggest that BP, the serum lipids concentration and obesity can be changed effectively by prison labour life, but are less readily changed in postmenopausal than in premenopausal women.