Objective:To determine epidemiology and antimicrobial susceptibility patterns of Vibrio(V.) cholerae O1 biotype EL Tor in summer outbreak of 2008 in Iran.Methods:Stool samples were collected from patients suspected to have cholera admitted to hospitals and clinics.Specimens examined by conventional bacteriological methods.All isolates were sent to cholera reference laboratory for further confirmation,stereotyping and susceptibility testing.Results:A total of 220 patients were diagnosed as cholera.All cases confirmed by Iranian reference health laboratory.One hundred ninety nine of 220 V.cholerae serotypes were Inaba and 21 serotypes were Ogawa.All cases were reported from thirteen provinces.The majorities of cases were from Tehran,Qum and Zahedan provinces with 56,26 and 25 cases respectively.24(11%) of patients were under 15 years old and 196(89%) of patients were older than 15 years.149(68%) of patients were male and 71(32 %) were female.129(59%) of patients had Iranian nationality,79(36.5%) were from Afghanistan and,12(5%) were from Pakistan.All isolates were resistant to co-trimoxazole,nalidixic acid,furazolidone,and intermediate to chloramphenicol and were susceptible to tetracycline, ciprofloxacin,and erythromycin.Conclusion:Our study reveals that in recent outbreak caused by V.cholerae EL Tor serotype Inaba is the predominant serotype.All isolates are resistant to cotrimoxazole. nalidix acid and furazolidon. Objective: To determine epidemiology and antimicrobial susceptibility patterns of Vibrio (V.) Cholerae O1 biotype EL Tor in summer outbreak of 2008 in Iran. Methods: Stool samples were collected from patients suspected to have cholera admitted to hospitals and clinics. bacteriological methods. All isolates were sent to cholera reference laboratory for further confirmation, stereotyping and susceptibility testing. Results: A total of 220 patients were diagnosed as cholera. All cases confirmed by Iranian reference health laboratory. One hundred ninety nine of 220 V. cholerae serotypes were Inaba and 21 serotypes were Ogawa. All cases were reported from thirteen province. The majorities of cases were from Tehran, Qum and Zahedan provinces with 56,26 and 25 cases respectively.24 (11%) of patients were under 15 years old and 196 (89%) of patients were older than 15 years.149 (68%) of patients were male and 71 (32%) were female.129 (59%) of patients had Iranian nationality, 7 All isolates were resistant to co-trimoxazole, nalidixic acid, furazolidone, and intermediate to chloramphenicol and were susceptible to tetracycline, ciprofloxacin, and erythromycin. ConCL: 9 (36.5%) were from Afghanistan and 12 Our study reveals that in recent outbreak caused by V.cholerae EL Tor serotype Inaba is the predominant serotype. All isolates are resistant to cotrimoxazole. Nalidix acid and furazolidon.