Objective A monoclonal antibody (Mab) against transporter associated with antigen processing (TAP)was prepared to study the function of TAP protein in the immunogenetics of ducks. Methods BALB/ c mice were immunizedwith fused Escherichia coli expression products containing peptide-binding region of TAP protein of major histocompatibilitycomplex (MHC) haplotype SPF ducks. Specific monoclonal antibodies were screened by ELISA, and truncated expressionmethod was used to identify the antigenic epitope. An indirect immunofluorescence assay was used to compare the reactivity ofMab against the peripheral blood lymphocytes of ducks and chickens. Immunohistochemistry was used to identify thespecificity of the Mab was detected against SPF chickens, SPF ducks, SPF pigs, common quails and geese. Results A duckTAP-specific monoclonal antibody was obtained and named as “1A6”. The antigenic epitope against 1A6 was identifiedroughly at 297NARHQMLQQAVLDATAGTGMVVQEAI322 by a trimmed expressed fusion protein. Chicken and duck peripheralbloodlymphocytes were tested positive for 1A6 in this indirect immunofluorescence assay. Immunohistochemistry of theduodenum from SPF chickens, SPF ducks, SPF pigs, Corturnix and geese by 1A6 was undertaken. Specific strong signals inimmunohistochemistry assay were detected in the duodenum of chickens and ducks, but not detected in the pigs, quails,geese or negative-control jejunum. Conclusions A monoclonal antibody specific to the TAP protein of chickens and ducks is obtained. It provides a useful material for studies of avian diseases and immunology of poultry.