The study was aimed to determine the Rota viral infection rates in diarrheic calves and effectiveness of some epidemiological factors on that rate in some provinces in Mid-Euphrates region in Iraq (Babylon, Al-Najaf, Karbala, Al-Qadisyia provinces). A total of 530 calves aged between 1-60 day were examined and fifty fecal (50) samples were collected from diarrheic calves only within six months period from November-2012 to April -2013. The fecal samples were examined for the presence of rotavirus by rapid rotavirus test (screening test), as well as the clinical examination for these diarrheic calves were done. The rapid test demonstrated that the rotavirus infection rate was 18/50 (36%). A 45.4% of rotavirus infection was found in calves less than 30 days of age which was significantly higher than 28.5% calves (30-60) days old. Male and female (37.5%, 40% respectively) were seen infected without any significant differences. The main clinical signs observed on rotavirus diarrheic calves were include, watery voluminous diarrhea with profound weakness and mild depression, so as temperature, respiration, heart rates could be decreased and appetite was changeable towards loss or anorectic. In Babylon, the highest rotavirus infection rate was recorded 60%, and less rates in Karbala 20% and 40%, 33% in AL-Najaf and AL-Qadisyia provinces respectively. The rotavirus infection rate in diarrheic calves was affected by months significantly, which it was higher at January 75%, so as in November 50%, December 40% and February 33.3%, but not recorded in March and April.