To investigate the clinical characteristics that significantly contribute to a decreased bone mineral density (BMD), the BMD changes and clinical characteristics of men who experienced a stroke between the ages of 50 years and 65 years were studied between 3 months and 4 months after the stroke. Subjects had a brain hemorrhage or a cerebral infarction. Only men aged 50 years to 65 years were included to eliminate postmenopausal osteoporosis and to eliminate the influence of senile osteoporosis. All subjects underwent a BMD test between 3 months and 4 months after their strokes. Also, patients with a medication history that might have caused a secondary osteoporosis before a stroke were excluded. The BMD for the lumbar spine and hemiplegic side of the femoral neck correlated significantly with the results of the manual muscle test (MMT) of the hemiplegic lower extremity and the Modified Barthel Index (MBI) score. This result suggests that the immobility from the decreased muscle strength and the weakened daily functionality might have reduced the BMD. According to a multiple linear regression analysis, the MBI score is significantly correlated with the lumbar BMD. The BMD of the hemiplegic femoral neck is significantly correlated with the MMT and the MBI score. This study showed that BMD monitoring should be considered in male stroke patients, especially for patients with a high dependency in daily functions and a decreased muscle strength in the hemiplegic lower extremity.