This study was designed to define the prevalence of colonization with antibiotic-resistant gram-negative rectal specimens were obtained from subjects residing in 2 pediatric extended-care facilities and were processed to identify gram-negative organisms resistant to ceftazidime, gentamicin, meropenem, and piperacillin-tazobactam. Horizontal transmission was assessed by analyzing all resistant isolates by pulsed-field gel electrophoresis. Forty percent of subjects were colonized with >/=1 resistant bacillus; >60% of organisms were resistant to >/=2 of the antibiotics tested. Colonization was disproportionate among residents with a tracheostomy or other prosthesis. More than 65% of colonized subjects shared 1 organism with another resident, with cross-colonization occurring among both enteric and nonenteric species. Children residing in chronic-care facilities represent a large reservoir for resistant bacilli. Such colonization may be amenable to simple barrier infection-control procedures.