Rapidly growing nontuberculous mycobacteria (RGMs) are responsible for a variety of clinical syndromes in humans including catheter-related blood stream infections (CRBSIs). Recently, we identified a cluster of RGM-associated CRBSI at our institution. We describe the epidemiologic and clinical patterns associated with these infections. We conducted a retrospective single-center review of RGM CRBSI between May 2004 and June 2005. RGMs isolated from blood cultures of 6 patients included Mycobacterium mucogenicum (2), Mycobacterium fortuitum (2), and the rare RGM species, Mycobacterium neoaurum (1) and Mycobacterium septicum (1). All of the patients had a long-term intravascular catheter (mean duration, 6.5 months). Bacteremia was resolved in all patients after catheter removal and appropriate antibiotics. None of the patients suffered a relapse of RGM CRBSI, and all survived to 1 year. RGMs are causative pathogens in both immunosuppressed and immunocompetent individuals with long-term intravascular catheters and blood stream infections. Recent trends at our center suggest that infections with these pathogens are rising.