ObjectiveTo investigate the antimicrobial resistance of extendedspectrum βlactamases(ESBLs) of Escherichia coli (E. coli) isolated from the First People’s Hospital of Kunming.Methods293 strains of E. coli were  isolated between January and December, 2006, ESBLs of E. coli were confirmed by phenotype confirmatory test, antimicrobial  susceptibility were detected by KirbyBauer method. Results168 of 293 (57.34%) strains of E. coli were ESBLsproducing strains. The main specimens isolated   ESBLsproducing strains was sputum (64.71%), the next were blood (62.50%) and pus (57.14%); Among departments, intensive care unit had the highest isolation rate of ESBLsproducing E. coli(65.22%), the next were department of endocrinology(65.00%) and oncology(63.33%). Except  imipenem and amikacin, the resistant rates  of ESBLsproducing strains against the other 14 antimicrobial agents  were significantly higher than nonESBLsproducing strains (all P<0.01); ESBLsproducing strains were resistant to penicillins,cephalosporins, aztreonam, quinolones, aminoglycosides and sulfonamides, the resistant rate to imipenem and amikacin was both <5%, which was 0.00% and 3.30% respectively. ConclusionThe prevalence of ESBLs is  high  among clinical E.coli isolates in  the First People’s Hospital of Kunming; ESBLsproducing strains are highly resistant to multiple antimicrobial agents, clinicians should choose antimicrobial agents rationally.