To estimate the prevalence of Schistosoma japonicum in field rodents, we conducted surveys of S. japonicum infection on 5 islands in the west Dongting Lake, China: Julinyuan, Jiangjiazui, Longwangmiao, Goutouzhou, and Niujiaojian. Thirty-five Rattus flavipectus, 43 Rattus norvegicus, 42 Rattus rattus, and 48 Microtus fortis were captured and examined from July to August 2011. Schistosoma japonicum was found in the 3 rat species but not in the vole M. fortis. No statistically significant differences in infection rates were found among the 5 locations or the 3 species of Rattus (P > 0.05). The average prevalence in the Rattus species was 14.2% (17/120), revealing that S. japonicum infection within field rodents was widespread in the Dongting Lake region. Wild rodents can be an important reservoir for S. japonicum transmission in the region and are of public health concern.