Emergence and dissemination of Enterobacteriaceae isolates harboring carbapenemases represent a significant threat to the management of nosocomial infections. The Ambler class D OXA-48 β-lactamase had been found only in enterobacterial species from Turkey. Here we describe a Klebsiella pneumoniae isolate (UCL-1) from a 37-year-old lymphoma patient in Belgium with reduced susceptibility to carbapenems. The isolate was resistant to amoxicillin/amoxicillin-clavulanate, susceptible to meropenem, intermediate to ertapenem, and resistant to fluoroquinolones, cotrimoxazole, kanamycin, and tetracycline. Etest showed imipenem/meropenem susceptibility and ertapenem intermediacy, and a crude β-lactamase extract exhibited significant carbapenem-hydrolyzing activity. PCR and sequencing identified the carbapenemase blaOXA-48 gene, which was surrounded by two IS1999 elements similar to the prototype K. pneumoniae 11978 strain from Turkey. Plasmid analysis detected a 70-kb self-conjugative plasmid (similar to pA-1 in the Turkish strain) that conferred reduced carbapenem susceptibility to Escherichia coli transconjugants. This is the first evidence of OXA-48-type carbapenemase identification outside Turkey in a patient with no apparent relation to the country. Automated systems (Phoenix, Vitek) may miss reduced carbapenem susceptibility, and low-level resistance may occur with additional mutations or plasmid transfer to bacteria with pre-existing reduced carbapenem susceptibility. Ertapenem seems more affected by these enzymes and is a better indicator for their detection.