Abstract Background & Aim: Rotavirus infection is the most common cause of dehydrating and gastroenteritis among children worldwide. . The aim of this study was to determine the prevalence of rotavirus in children hospitalized with acute gastroenteritis in Imam Sajjad Hospital of Yasuj. Methods: This cross sectional – descriptive study was done on 184 stool samples of children younger than 7 years of age hospitalized at Imam Sajjad hospital of Yasuj in 2011 due to acute gastroenteritis. All samples were routinely analyzed for detection of rotavirus by Enzyme Immunoassay (EIA) test. Data was analyzed by SPSS version 16, Chi-square test and Fisher's exact test. Results: Of the 184 samples analyzed, 52(28.26%) were positive.The Results showed significant relationship between the seasonal distribution and virus detection (p=0/001). The highest incidence of rotavirus was seen in autumn with frequency of (48.08%) and the lowest in spring (5.77%). Conclusions: According to high prevalence of rotavirus infection, continual surveillance is necessary to provide useful data for formulating effective vaccines and perform diarrhea prevention programs. Key words: Rotavirus, Gastroenteritis, Prevalence, Elisa