This review covers the recent findings on extended spectrum beta-lactamases (ESBL) pathogens, focusing on the epidemiology of infection due to this pathogen. Use of ESBL is growing rapidly and widely. CTX-M-15 producing ESBL Escherichia coli is the most commonly encountered in clinical practice. In general, ESBL infections are represented by urinary tract infections, but they can also cause fatal infections involving the vascular system and central nervous system. Because E. coli is a common colonizer of normal intestine, increasing prevalence of ESBL-producing pathogens is particularly troublesome. In a situation where ESBLs are disseminated in the community, the ideal control of this multidrug-resistant pathogen will be challenging. Precise data on the prevalence and risk factors of ESBL-producing microorganism are still undetermined. More epidemiological studies are needed for the question to be answered. In order to maximize efficiency of treatment, information on the trend of increasing numbers of ESBLs is also needed on persistence of ESBLs in carriers as well as better understanding of how antibiotic treatment and other risk factors affect their persistence and further dissemination. The global emergence of multidrug-resistant ESBL pathogen has recently led to critical treatment problems. Early detection, adequate antibiotic therapy, and effective prevention are necessary for achievement of a safe community.