BACKGROUND Invasive infections caused by coryneform bacteria are uncommon but have been reported with increasing frequency in recent decades, especially in immunocompromised persons. Because pediatric experience is limited, we examined the epidemiology and clinical characteristics of these infections in children undergoing cancer therapy. METHODS Using strict case definitions, 17 coryneform bacterial infections were identified in 16 children during a 13-year period; there were 12 episodes of bacteremia and 5 skin or soft tissue infections. RESULTS The median age of children with bloodstream infections was 11.2 years, and that of children with skin or soft tissue infections was 3.5 years. Most were receiving cancer therapy at the time of their infections, were outpatients at the onset of their infections, had central venous catheters, and were not neutropenic. No patient died as a result of infection and most had relatively mild signs and symptoms. All patients responded promptly to antimicrobial therapy and, although 3 infections relapsed, there was only 1 serious complication. The most common species isolated were Corynebacterium striatum, C. amycolatum, and Microbacterium species. CONCLUSIONS The epidemiologic and clinical features of coryneform bacterial infections in immunocompromised children differ in several important respects from the previously reported characteristics of these infections in adults.