We studied the presence of β-lactamases with an extended spectrum of activity in clinical Escherichia coli isolates from Cairo, Egypt. Forty-six E. coli isolates were collected from patients with urinary tract infections at a university hospital in 2001. Phenotypic characterisation identified a very high extended-spectrum β-lactamase (ESBL) rate of 60.9%. Pulsed-field gel electrophoresis and plasmid profiles revealed eight different clonal groups. All ESBL producers were polymerase chain reaction-positive for bla_TEM and bla_CTX-M genes. Within the CTX-M family, three different enzymes, CTX-M-14, CTX-M-15 and CTX-M-27, were found. The ESBL producers carried multiple plasmids and further plasmid-encoded resistances. In several strains, genes for up to six aminoglycoside-modifying enzymes were detected. A linkage to fluoroquinolone resistance was not observed. This study confirms the high rate of ESBLs in Egypt and further demonstrates the worldwide spread of genes coding for CTX-M enzymes in clinical isolates.