In order to evaluation of prevalence of rotavirus and/or coronavirus, forty suckling Korean indigenous calves (between 2 and 98 days old) with acute diarrhea were investigated by the immunochromatographic rapid test in the field (veterinary practice) on October and on December 2006. Rotavirus and coronavirus were detected in 13 (32.5%) and 8 (20.0%) of the fecal samples from diarrheal calves, respectively. The highest mortality rate in diarrheal calves occurred in the neonatal period from 2 to 7 days old. Totally, 40.0% of diarrheal calves showing acute enteritis were not detected with rotavirus and/or coronavirus. The rotavirus infection rate was significantly difference (p<0.05) between October and December, and the detection rate of rotavirus was bigger than that of coronavirus. These results suggested that rotavirus can be frequently associated with acute diarrhea of suckling calves and affected with changes of temperature.