Background/aim: The aim of this study was to determine the prevalence of fecal carriage of extended-spectrum beta-lactamase (ESBL)producing bacteria, enzyme types, and risk factors affecting colonization.,Materials and methods: A total of 576 stool samples from outpatients were examined between October 2012 and May 2013. Screening was done with selective EMB plates. ESBL were detected by double-disk synergy and confirmed agar strip gradient methods. Enzyme types were determined by PCR.,Results: The prevalence of fecal carriage was found as 30% (173 of 576). Recent use of antibiotics, hospitalization and surgical operation, diabetes, crowded household populations, and old age were associated with higher carriage rates. Of the ESBL-producing bacteria, 87.5% were positive for bla(CTX-M) genes. Of the bla(CTX-M) gene-positive isolates, 95.2% were positive for bla(CTX- M-1) genes; among these, 82.2% were positive for bla(CTX- M-3) and 67.7% were positive for bla(CTX- M-15) genes while 62.5% isolates were positive for both bla(CTX- M-3) and bla(CTX- M- 15) genes,Conclusions: A high rate (30%) of fecal carriage of ESBL bacteria was found in an adult population. The predominant beta-lactamase enzyme types were CTX- M- 3 and CTX- M- 15.