Calf diarrhea is a common syndrome causing colossal economic losses.Rotavirus and Coronavirus are major pathogens of calf diarrhea. During the period of investigation (13 consecutive months), a total number of 140 neonatal calves were carefully examined and thereafter subjected to serological and molecular diagnosis for the diagnosis of Rota and Corona viruses' infection. The serological and molecular diagnosis by using LAT and RT-PCR indicated that positive samples of Rotavirus infection were 21.43% (30/140) and 8% (4/50), respectively. ELISA and RT-PCR were used in diagnosing of BCoV infection and found that positive samples were 2.13% (2/94) and 4% (2/50), respectively. The Prevalence of Rotavirus and Coronavirus infection was 21.43 % (30/140) and 2.13 % (2/94) of the examined calves, respectively. It was found that there was a strong negative correlation between age of examined calves and Rotavirus infection. Coronavirus infection was found in calves at >4-7 weeks. There were no significance difference in Rota and Corona viruses' infection and sex, breed and species of examined calves. The most positive cases of Rotavirus and Coronavirus infection were reported in cold months. The lower infection rate of Rotavirus was recorded in hot months.It is concluded that Rota and Corona viruses play an outstanding role in causing enteritis in neonatal calves in different localities of Assiut governorate.