OBJECTIVE To evaluate the frequency of radiologic and histologic manifestations of matrix calcification in chondromyxoid fibromas. METHODS Forty-four cases of chondromyxoid fibroma were reviewed. The age range of the patients was 3-70 years (average 29 years). RESULTS Calcification was found microscopically in 15 cases (34.1%). In five cases (12.5%) it was demonstrated on plain films or CT. The age range of the patients with microscopic evidence of calcified matrix was 14-70 years (mean 46 years), while that of the patients with non-calcified lesions was 3-59 years (average 21 years). All but two of the patients who showed microscopic calcification in the tumors were over 40 years of age. Four microscopic patterns of calcification were observed: coarse granular, circumscribed, trabecular, and "chicken-wire." CONCLUSIONS Calcification in chondromyxoid fibroma was found more frequently than in previously reported studies. There was a tendency for this phenomenon to occur in the tumors of older patients, particularly those over 40 years old, and in chondromyxoid fibromas situated in flat bones, including ribs.