The Singh index was used to measure the degree of osteoporosis in patients with fracture of the neck of the femur and to compare its prevalence with a random population sample in Jerusalem. The frequency of osteoporosis was 22.7% among women in the fracture series as compared with 1% in the control group. These figures are much lower than those in comparable series. The Singh index was not as sensitive an indicator of spinal osteoporosis as a direct measurement of vertebral bone density and could not be correlated with the incidence of hip fractures.