This study includes the clinical features of diabetic patients with fascial space infections of head and neck and those of non-diabetic patients. We retrospectively studied 62 patients who were treated for fascial space infections of the head and neck, and compared the patients’ background, the aetiology of the infection, clinical variables, laboratory values, and treatment process. Statistical analyses of the differences between groups were made with Student's t test, the chi square test, and analysis of variance, as appropriate. Diabetic patients had more spaces involved, had longer hospital stays, and developed more complications. The main microorganism of diabetic group was Klebsiella pneumonia and otherwise, Streptococcus spp. was for non-diabetic group. We conclude that diabetic patients are more likely to develop complications and it is necessary to consider about dominant microorganism when using medication for diabetes patients