Objective To investigate drug-resistance and the genotypes of extended-spectrum ? lactamases (ESBLs) producers in Beijing Tiantan Hospital and Beijing Chaoyang Hospital. Methods Standard agar dilution method, transconjugation test, isoelectric focusing, DNA sequencing were preformed in 52 clinical isolates of Escherichia coli and Klebsiella pneumoniae. Results ESBLs producers were resistant to many antibiotics. DNA sequencing of amplicons of 52 strains revealed that ESBLs-encoded genes were CTX-M-14, 22,24 and SHV-2,12,respectively. Conclusions We should pay great attention to detect ESBLs producers and investigate their genotypes, so that we could prevent regional prevalence of ESBLs producers and utilize antibiotics reasonably.