Increasing prevalence of infections caused by multiresistant gram-negative enteric bacilli due to synthesis of extended-spectrum beta-lactamase (ESBL) or to desrepressed chromosomic AmpC beta-lactamase (AmpC) is a major concern in the hospitalized patient population. Renal transplant recipients are especially susceptible to these infections. A cohort observational study in a 3-year period was performed. ESBL-production was determined by phenotypic analysis based on the CLSI recommendations. A multi-variate logistic regression analysis was performed to identify independent variables associated with multi-resistant gram-negative bacilli infection. The study included 417 patients (61 double kidney-pancreas recipients). The incidence of ESBL-producing and desrepressed chromosomic AmpC beta-lactamase resistance was 11.8% (49 patients). The most frequent bacteria isolated was E. coli (35/60 isolations), followed by Klebsiella spp(12/60 isolations). Double kidney-pancreas transplantation(OR 3.5, CI95% 1.6-7.8), previous use of antibiotics(OR 2.1,CI95% 1.1-4.1), posttransplant dialysis requirement (OR 3.1, CI95% 1.5-6.4) and posttransplant urinary obstruction (OR 5.8, CI95% 2.2-14.9) were independent variables associated with these multiresistant gram-negative enteric bacilli infections. The incidence of ESBL-producing and desrepressed AmpC beta-lactamase gram-negative enteric bacilli infection in our population was high. These infections are associated with significant morbidity after renal transplantation.