The results of 179 radionuclide bone imaging examinations, 105 gathered retrospectively from the cases of 97 patients referred for assessment of possible occult fracture of the proximal femur (hip) and 74 performed prospectively on 63 patients referred with a diagnosis of obvious or suspected hip fracture, were analyzed in relation to patient age, the interval between injury and imaging, and the type of fracture sustained. Ninety-two examinations were performed less than 72 hours after injury; 31 of these were done at 0-24 hours. For the diagnosis of hip fracture in an individual patient, the overall sensitivity was 0.933; specificity, 0.950; positive predictive value, 0.918; and negative predictive value, 0.960. For the clinically important subgroup of 145 patients with normal or equivocal radiographs, the sensitivity was 0.978. A characteristic pattern for greater trochanter fractures was found. Other diagnoses were scintigraphically established in 41% of patients evaluated. The data suggest that patients of all ages, regardless of the time after injury, can be imaged as soon as they present.