Resistance to imipenem and meropenem was observed in 211 (16.5%) isolates of Pseudomonas aeruginosa recovered in a Greek university hospital during 1996 to 1998. In six isolates selected from throughout this period, high-level resistance to both carbapenems (MICs greater than or equal to 128 mu g/ml) was associated with production of the class B beta-lactamase VLM-1. bla(VIM)-bearing isolates belonged to serotype O:12 and were indistinguishable by pulsed-field gel electrophoresis.