Prevalence of Extended-spectrum __ampersandsignbeta;-lactamase (ESBL)-producing organisms is increasing in healthcare associated (HCA) institutions and community. We conducted a matched case-double control study to assess the risk factors for acquisition of these multi-drug resistant organisms (MDRO), in a cardiac center in Brazil. We studied two hundred and thirty-eight patients (58 cases). Two groups of comparison were included: control Group 1 (N=120), with patients without infection; and control Group 2 (N=70), with patients with infection by non-ESBL producers Klebsiella spp., E. coli or Proteus mirabilis. On multivariate analysis, risk factors for hospital acquisition of ESBL-producing organisms were as follows: previous use of second-generation cephalosporins (OR 5.73; 95% CI 1.30-25.31), fourth-generation cephalosporins (OR 3.62; 95% CI 1.24-10.53) and metronidazole (OR 11.68; 95% CI 1.20-114.00). Previous identification of MDRO (OR 8.98, 95% CI 1.61-50.18), number of days on antibiotic use (OR 1.12; 95% 1.04-1.20) was also independently associated with ESBL-producing organisms. Interestingly, the presence of other MDRO in ward (OR 0.30; 95% CI 0.13-0.71) was associated as a protector factor for ESBL identification. When there was a low consumption of third-generation cephalosporins and quinolones, the second- and fourth-generation cephalosporins and metronidazole were, associated with ESBL-producing bacteria. In addition, adherence to isolation precautions and infection control recommendations can help to prevent ESBL-resistance dissemination.