Five hundred fecal samples from diarrheic daity calves (under I month old) collected from7 regions in Tehran, between October 1998 to October 1999. Samples were screened for group A bovine rotavirus (BRV) using antigen capture enzyme - linked immunosorbent assay (AC-ELISA). The overal prevalence of BRV infection was 28.8%. Twenty four BRV positive samples were randomely selected and serotyped by AC-ELISA using G and G,0 monoclonal antibodies. Analysis of these samples revealed that 10 (41.7%) were
and 8 (33.3%) were G,0 Positive. Two samples (8.3%) were Positive for both G6 and G10 Serotypes. Four samples (16.7%) were found to be untypeable (G and G, negative).