We have compared the computed tomographic(C. T.) findings with those of conventional roentgenogram(simple AP and lateral radiograms) in 18 cases of osteochondritis dissecans of the capitellum humeri available for review. Among the 18 cases, 2 cases of them had a lesion of osteochondritis dissecans on C. T. which, however, had not been found on conventional rentgenograms. Fro the 5 cases, which had not clearly found on conventional rentgenograms, 2 loose body on conventional view, 3 cases had different numbers and locations of loose body on C. T. films. On the bases of our findings, we recommend that C. T. is necessary in early detection and the determination of anatomical location and status of osteochondritis dissecans of capitellum.