Radiographic density is considered an important feature in the evaluation of noncalcified breast masses, yet no studies assessing its value have been published. The radiographic densities of 91 biopsy-proved, nonfatty, noncalcified breast masses were evaluated by three mammographers. The density determinations made by each observer were compared with the histologic outcome for the 51 benign and 40 malignant lesions. With the kappa statistic, interobserver agreement was relatively poor (0.22 to 0.49), and intraobserver agreement for one expert mammographer was 0.50. When the majority opinion of the mammographers was used, sensitivity was 48%, specificity was 80%, and both positive and negative predictive values were 66%. As a solitary feature in lesion analysis, mammographic density is difficult to assess and is of limited value for the prediction of the benign or malignant nature of noncalcified breast masses.