Background: Healthcare associated infections (HAIs) caused by AmpC β-lactamases producers are clinically significant as they can mediate resistance to cephalosporins, penicillins, monobactams and cephamycins. Objectives: To find out the prevalence of AmpC producers among Gram-negative bacilli recovered from HAIs in adult intensive care units (ICUs) and to identify the risk factors associated with AmpC β-lactamases production. In addition, we compared the antimicrobial resistance patterns in AmpC positive and negative isolates. Methodology: A prospective study was conducted over one year duration on samples collected from patients suffering from HAIs in the adult ICUs of Mansoura Emergency Hospital, Mansoura- Egypt. Isolated Gram-negative bacilli were subjected to cefoxitin disk diffusion test to screen for AmpC production. Presumptive AmpC producers were then confirmed by AmpC disk test, disk approximation test and AmpC E test. Results: Out of the recovered 240 Gram-negative bacilli, 73 isolates (30.4%) were AmpC producers. Acinetobacter baumannii represented the highest AmpC production (44.4%). Significant risk factors for AmpC β-lactamases production included previous exposure to antibiotic therapy, prolonged duration of antibiotic therapy before development of HAIs and presence of a central line or endotracheal tube. Resistance to all tested antimicrobials, with the exclusion of imipenem and meropenem, was significantly associated with AmpC producers. Conclusion: Increased prevalence of AmpC producers among Gram-negative isolates was observed in our study. Thus, early detection of AmpC producing bacteria is necessary to avoid treatment failure. Establishment of antibiotic stewardship policy and enhanced infection prevention and control measures are necessary to avoid spread of resistant infections in ICUs.