The aim of the study was to examine clinical and subclinical BRV and BCV infection rates in calves and serologic prevalance of cows in northern Turkey. In this study, 100 fecal specimens collected from healthy calves (0-3-months-old) and calves with diarrhoea were examined for bovine rotavirus (BRV) and bovine coronavirus (BCV) antigens, with 23% and 1% positivity detected respectively. BRV antigen positivity was 4.08% in healthy calves but BCV antigen was not detected. BRV and BCV antigen positivity was 41.17% and 1.96% in calves with diarrhoea. Antibody titers against BRV and BCV in 256 adult cows sampled in the same region were 71.48% and 98.43%, respectively. As the result, it is concluded that BRV-sourced infections in calves with diarrhoea are frequently encountered (41.17%), but BCV infections are rarely detected (4.08%). In contrast, BCV infection in cows are more frequently encountered than BRV infections in Northern Turkey. Data from this study reflects the widespread distribution of BRV infections in 0-3-month-old animals and BCV infections in animals older than 3 months.