Precipitating antibodies to the Cu-1 strain of infectious bursal disease (IBD) virus were detected in sera and yolk of turkeys. Three IBD virus isolates were recovered from infected turkey poults. Experimental infection with one isolate and with the highly pathoge nic Cu-1 strain was conducted. Successful reproduction of the disease was achieved by the isolated virus. Lesions were described and discussed. The isolate was antigenically related to but not identical with the known Cu-1 IBD virus strain.