Strains of Klebsiella pneumoniae producing KPC-carbapenemase have emerged as one of the most important multidrug-resistant Gram-negative nosocomial pathogens. Here, we report the first isolation and subsequent dissemination of a K. pneumoniae ST512 producing KPC-3 carbapenemase in a hospital in southern Italy. Isolates were obtained from blood, throat swabs, sputum, catheters, and urine of patients admitted to different hospital wards. Antimicrobial MICs were determined for all isolates by automated systems and confirmed by Etest. Carbapenemase production was confirmed by the modified Hodge test and by a disc synergy test, and carbapenemase genes were investigated by PCR. All isolates were characterized by pulse-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) analysis. Most isolates were multidrug resistant with exception of some isolates intermediately susceptible to gentamicin, tigecycline, and trimethoprim-sulfamethoxazole. PCR analysis showed that isolates harbored the blaKPC-3 gene associated with blaTEM and blaSVH. PFGE and MLST showed that all isolates belonged to the same ST512 clone recently described in Israel.