The aim of this study was to examine the epidemiological features of Eimeria in calves with acute diarrhea. Samples were collected from between 15 days and 90 days old calves (n=83) in Gimje area from March 2006 to March 2007. Feces of bloody diarrhea were examined for the presence of Eimeria oocysts using a sucrose flotation method. Out of 83 calves, 62 (74.6%) had Eimeria oocysts. In the results of monthly analysis, the highest prevalence (12.0%) of Eimeria oocysts was found on June. In the seasonal infection rate, spring was the highest prevalence (30.1%), followed by summer (24.0%). Furthermore, the highest prevalence (44.5%) was found in calves from between 31 - 60 days old in the analysis by ages. However, there was no significant differences between female and male sex even though the prevalence was slightly bigger in female than in male. The prevalence of the present study to detect Eimria oocysts for infection may have been affected by weather-conditions in the spring. Young calves should be separated to minimize the infection from cattle as much as possible. Additional studies are necessary to find other factors for infection and combining molecular methods with a highly sensitive system for Eimeria detection could be a reliable and economic way of Eimeria eradication.