As part of the worldwide Study for Monitoring Antimicrobial Resistance Trends (SMART), a total of 3,030 clinical isolates of gram-negative bacilli from intra-abdominal infections were collected from 43 hospital centres from 13 European countries during 2008. Of 51 species, the most commonly isolated species were Escherichia coli (49.3%), followed by Klebsiella pneumoniae (10.5%) and Pseudomonas aeruginosa (8.6%). Respectively, 17.9%, 11.6%, 5.5% and 4.5% of K. pneumoniae, E. coli, Proteus mirabilis and K. oxytoca were extended-spectrum beta-lactamase (ESBL)-positive. All isolates were tested using a panel of 12 antimicrobial agents, and susceptibilities were determined using European Committee on Antimicrobial Susceptibility Testing (EUCAST) clinical breakpoints. The most active agents against the study isolates (including those producing ESBLs) were amikacin, ertapenem and imipenem. Overall, with the exception of the carbapenems, most agents exhibited dramatically reduced susceptibilities against ESBL-positive and multi-drug-resistant isolates.