Turkey immunoglobulin (Ig) isotypes IgG and IgM were isolated from blood and IgA was isolated from bile. Isolation was accomplished by gel filtration of the ammonium sulphate cut on Sephacryl S-200. Using immunoelectrophoresis and indirect ELISA, the cross-reactivity between antibodies, of monoclonal and polyclonal origin, specific for the Ig isotypes of chicken, and the purified turkey Ig isotypes was evaluated. Commercially available polyclonal antibodies, anti-chicken/IgA (alpha-chain specific, affinity purified), anti-chicken/IgG (Fc-fragment specific) and anti-chicken/IgM (mu-chain specific) showed an interspecies cross-reactivity with the corresponding turkey Ig isotypes. The monoclonal antibody (MAb) AV-G3 specifically detected turkey IgG, whereas MAb M1 reacted exclusively with turkey IgM. This panel of anti-immunoglobulins represents a useful tool for examining the humoral immune responses of turkeys.