On the basis of the findings of nine of our patients and our review of previously reported cases of diffuse sclerosing osteomyelitis and chronic recurrent multifocal osteomyelitis, we discuss the similarity of these two entities. Our nine patients had initially been given diagnoses of diffuse sclerosing osteomyelitis on the basis of their clinicopathologic findings. However, technetium 99m-MDP bone scans performed on four of them revealed multiple bone lesions leading to the diagnosis of chronic recurrent multifocal osteomyelitis. Furthermore, no clear difference between clinical features in the patients with multiple bone lesions and those in the patients with diffuse sclerosing osteomyelitis was found. We conclude that diffuse sclerosing osteomyelitis is an expression of chronic recurrent multifocal osteomyelitis.