THE FLUORESCENT ANTIBODY (FA) TEST FOR THE DIAGNOSIS OF FIELD OUTBREAKS OF TRANSMISSIBLE GASTROENTERITIS (TGE) IN BABY PIGS WAS COMPARED TO OTHER AVAILABLE MEANS INCLUDING: virus isolation by inoculation of test pigs, intestinal lesions especially villous atrophy, and clinical observations. Immunofluorescent tests were done on frozen sections of the small intestine and it was possible to make a specific diagnosis within two hours after collecting samples. The results obtained with the FA test compared favorably with virus isolation from infected tissues. It was considered a more advantageous procedure as long as infected pigs were in a relatively early phase of the disease. Because of the variability of the lesions as related to the stage of infection, pathologic diagnoses were less satisfactory. Field diagnoses made on the basis of clinical signs were least reliable.