In this study, we cloned the TAP1, TAP2a, and TAP2t genes from grass carp （Ctenopharyngodon idella）, and analyzed their phylogeny. It was found that grass carp TAP genes are conserved. Structural prediction of TAP proteins revealed that grass carp TAP proteins possess multiple transmembrane regions and have typical structural features of the ATP-binding cassette transporter （ABC） superfamily. Grass carp TAP1, TAP2a, and TAP2t genes were highly expressed in the spleen and kidney, and significantly up-regulated at 72h after infection with Aeromonas hydrophila. In the primary head kidney leukocytes, stimulation with phytohemagglutinin （PHA） and polyinosinic-polycytidylic acid [poly（I： C）] up-regulated all TAP genes, and that with interferon gamma （IFN-γ） and interleukin 1 beta （IL-1β） induced the expression of TAP1 and TAP2t but not TAP2a. In the EPC cells, infection with Spring viraemia of carp virus （SVCV） elevated the expression levels of TAP1 at 12 h, 24 h, and 36 h and TAP2t at 12 h, suggesting they are involved in immune response to SVCV infection. The findings provide valuable information for further investigation on MHC I antigen presentation pathway in fish.