During this study, 134 samples have been examined for the detection of the viruses associated with neonatal calf diarrhea. The presence of Nebraska viruses (rotavirus and coronavirus) has been demonstrated by using the electron microscope and the fluorescent antibody techniques while the presence of other viruses has been detected by the observation of a cytopathic effect on monolayer cells of calf testis. The Nebraska viruses have been demonstrated in 107 (80%) out of 134 field case specimens. An association of rotaviruses and coronaviruses was found in 58 cases (54%) whilst the coronaviruses and the rotavirus were found singly in 34 cases (53%) and in 15 cases (14%) respectively. Four bovine virus diarrhea viruses, two infectious bovine rhinotracheitis viruses and two enteroviruses have also been isolated in the preceding 107 Nebraska positive specimens. For the detection of the Nebraska viruses, the fluorescent antibody techniques were more sensitive than the electron microscopy. However, those two techniques must be used simultaneously for a better detection of a greatest possible number of cases.