Towelve calves of 4-10 months old with clinical signs suspected to bovine viral diarrhea virus (BVDV) infection were selected for this study. Histopathologic sections were performed on formalin fixed paraffin-embded ear notch biopsies, mounted on poly-L-lysine coated slides and stained for BVDV by Anti-BVDV monoclonal antibody labelled with fluorescein isothiocyanate. Stained sections were examined by fluorescent microscopy for detection of green fluorescent evidence within the cytoplasm of keratinocytes, other dermal cells and chondrocytes. Detection of BVDV antigen in buffy coat cells was performed by using a commercially available antigen-capture ELISA kit, and RT-PCR, using a universal primers set, specific for all pestiviruses. Based on 11 positive cases detected by RT-PCR, immunofluorescent staining and antigen-capture ELISA could detect 8 cases (72.72%) and one case (9%) respectively. Results of this study suggest immunofluorescent test on ear notch biopsies has a relatively high sensitivity, and can be used as a reliable and feasible method for detection of calves with acute infection with BVDV.