The bottle-nosed dolphin (Tursiops truncatus) interferon-gamma(IFN-gamma) cDNA was cloned from mitogen stimulated peripheral blood mononuclear cells (PBMC) RNA utilizing the reverse transcription-polymerase chain reaction (RT-PCR). The dolphin IFN-gammacDNA was 585 base pairs in length and contained an open reading frame of 498 nucleotides encoding an IFN-gammaprecursor of 166 amino acids, with cleavage of the putative signal peptide of 19 amino acids. Analysis of the mature amino acid sequences revealed two potential N-linked glycosylation sites. Comparison of the predicted amino acid sequence showed that dolphin IFN-(gamma)shares 86, 85, 63 and 42% similarity with the bovine, ovine, human and mouse IFN-gamma, respectively.