INTRODUCTION AND OBJECTIVES: Corynebacterium striatum (C. striatum) is known to colonize the skin and mucous membranes of most normal human hosts. While it is frequently isolated in clinical laboratories, the clinical significance of C. striatum is often unknown with respect to diabetic foot infections with osteomyelitis. There have been very few studies published on this topic, and even fewer that report on treatment courses. To our knowledge, there has been no study published reporting diabetic foot osteomyelitis with isolation of C. striatum from bone culture. METHODS: Four patients were known to have been treated at our facility for C. striatum diabetic foot osteomyelitis. The medical records for each patient were thoroughly reviewed with close attention directed towards the past medical history, wound duration, wound and bone cultures, antimicrobial therapy and clinical outcomes. RESULTS: Bone cultures of all 4 patients were notable for C. striatum. Diphtheroids were also noted on wound cultures for 3 patients which were not speciated. All bone cultures were obtained during surgical treatment of the diabetic foot infection. All patients were type II diabetics but varied with respect to age and gender. All patients were treated with an extended course of antibiotics and/or surgical resection of osteomyelitis. Patients were followed until complete wound closure. CONCLUSIONS: We report four cases of diabetic foot osteomyelitis in which C. striatum was noted and treated as a pathogen. Diphtheroids are often overlooked as a potential pathogen in diabetic foot infections and rarely treated as such. However, our findings suggest that clinicians should consider C. striatum as a possible cause of osteomyelitis, especially when patients fail to completely heal wounds in a timely manner that have previously and repeatedly displayed Diphtheroids from cultures.