This study aims to determine resistance pattern and the prevalence of extended-spectrum beta-lactamase (ESBL) among 250 Escherichia coli in Riyadh and to determine the antimicrobial resistance determinants for ESBL positive E. coli (ESBL-EC) which collected from urine during 2012. MICs were determined. Phenotypic and genotypic screening of ESBL were carried out. PCRs were used to detect resistance determinants in ESBL-EC for tetracycline, chloramphenicol, streptomycin and sulphonamides. The overall resistance for streptomycin and sulphamethoxazole was 100%, however the resistance rates for amoxicillin, tetracycline, chloramphenicol, amoxicillin/clavulante, trimethoprim, sulphamethoxazole/trimethoprim, gentamicin, amikacin, ciprofloxacin, cefotaxime, ceftazidime, aztreonam, cefepime and nitrofurantoin were 96%, 85%, 83%, 71%, 70%, 62%, 42%, 29%, 25%, 22%, 21%, 20%, 17% and 5% respectively. The whole collection was susceptible to fosfomycin, imipenem, tigecycline, cefoxitin, and colistin. Of 250 isolates, 21% were positive for ESBL. bla_{CTX-M-15-like} was detected in all ESBL-EC. Among ESBL-EC, the prevalence of tet(B), tet(A), tet(A), catI, cmlA, strA, strB, aadA, sul1, sul2,and sul3 was 89.9%, 8.2%, 2%, 88.9%, 51.11 %, 100%, 100%, 88.46%, 78.84%, 92.31%, 21.15%,  respectively. The bla_CTX-M-15-like, bla_TEM–like catI, tet(B), sul2, strA, strB, and aadA genes were the most prevalent resistance determinants. This study provides baseline data regarding the molecular bases of antimicrobial resistance in ESBL-EC from Riyadh.