Background: Enterobacteriaceae rapidly acquire resistance to antibiotics by beta-lactamase production, enzymes that inactivate beta-lactam antibiotics. Objective: To determine the prevalence of extended.spectrum β-lactamases (ESBLs) and inducible β-lactamases (AmpC) in Enterobacteriaceae isolated in the Hospital Rosario Pumarejo de Lopez from Valledupar between Janu- ary and July 2009. Materials and Methods: Retrospective study that included all positive Enterobacteriaceae culture isolated from patients from different hospital areas. Results: We analyzed 146 reports, the higher frequency was found in outpatient services (31.5%) and emergency (21.23%), and urine samples (50%) and wounds (32.19%). Escherichia coli was the most frequent (58.9%), 18 enterobacteriaceae (12.3%) were ESBL -producing, E. coli and K. pneumoniae were the most frequent (55.6% and 23.2% respectively). The ESBL phenotype was obtained from the inpatient service (33.3%) and wound samples (50%), the rasistance pattern was variable to penicillins, third generation cephalosporins and aztreonam. Cross re- sistance between these antibiotics and non β-lactam antibiotics (quinolones, sulfonamides, and aminoglycosides), and sensitivity 100% to carbapenem were found in this study. Enterobacter cloacae, Enterobacter aglomerans and Serratia marcescens produced AmpC β-lactamase (2.05% each). Conclusion: E. coli and K. pneumoniae were the most frequent Enterobacteriaceae producing ESBL with moder- ate resistance phenotypic profile to beta-lactam and non beta-lactam antibiotics. increase the control measures iotics especially third generation cephalosporins that contribute to the ence of new strains with this type of beta-lactamases.