Implant infection remains a feared complication after total hip replacement. A higher rate of infection is observed after revision surgery. An additional threat for such patients arises from the fact that bacteria resistant to a multitude of antibiotics are encountered with increasing frequency in the hospital setting. Among them enterobacteria producing extended spectrum beta-lactamases (ESBL) are the second most frequent group of multiresistant isolates. ESBLs are enzymes which hydrolyse third and fourth generation cephalosporins resulting in a distinctive resistance against these antibiotics. Even though ESBLs were first described in the early 1980's and now represent pathogens of importance in intensive care units, they have been only rarely encountered in orthopaedic and trauma surgery. We report on three cases of ESBL-associated infections in hip arthroplasty, resulting in 1) resolution of infection after removal of the hip implant, 2) death after developing a nosocomial pulmonary infection due to ESBL-producing bacteria, and 3) resolution of infection after two-stage revision. The infections, caused by multi-resistant ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates, demonstrate the difficulties in managing implant associated infections with resistant bacteria, and emphasize the importance of recognizing ESBL-positive bacteria as increasingly important pathogens that require special precautions and treatment. Our observations suggest that ESBL-expressing bacteria in orthopaedic and trauma surgery are not a rare phenomenon any more.