The aim of the present study was to characterize extended-spectrum b-lactamase (ESBLs) genes in multidrug resistant enterobacterial pathogens as well as commensal isolates from the Sudan during the period 2003 to 2007. ESBL production was determined phenotypically by the combined disc method, and was characterized genotypically by the detection of blagenes by PCR and nucleotide sequencing. Transferability was examined by conjugation with nalidixic-acid resistant E. coli K12. The results showed that a total of 106 of the 113 (94%) isolates including E. coli, Klebsiella pneumoniae, Proteus spp., Enterobacter cloacae, Providencia spp. and Morganella morganii, were positive for blagenes including the prototype blaTEM. Eleven isolates (28%) of the 113 were ESBL producers encoding blaSHV genes (SHV5, SHV5a, SHV12, SHV26, SHV28 and SHV38), 90 isolates (80%) were CTX-M positive. All, but only one (CTX-M9) were CTX-M15. Only 3(2.7%) of the isolates were Amp-C producers (CMY-4 and DHA-1). Plasmid transfer of the multiple resistance patterns was achieved among all the isolates. These findings demonstrated that ESBLs were highly produced by multi-resistant enterobacterial isolates from the Sudan; among both clinical pathogens as well as stool commensals. This is the first report of ESBLs genes characterization from  the Sudan.