Abstract: We measured the super-extremity bone mineral content and bone mineral density (BMD) of ra-dius in 50 patients with malignancy. BMD was mean 0. 362±0. 071g/cm². 40 patients (80% )had low BhfD. The authors presumed that BMD in the healthy subjects of same sex and age group minus 2SD was the diagnostic criteria of the bone mineral reduction in patients with malignancy. BMD in patients with malignancy was significantly lower than that in the healthy subjects (Ｐ＜0.05)·A close correlation was found between the reduction of BMD and the disease duration. The results in-dicates that most patients with malignancy have reduction of BMD. The reduction of BMD is the pe-culiar and sensitive index of the loss of bone mass.