The bottle-nosed dolphin (Tursiops truncatus) IL-1α and IL-1β cDNA were cloned from mitogen stimulated peripheral blood mononuclear cells (PBMC) RNA utilizing the reverse transcription-polymerase chain reaction (RT-PCR). The sequences of these cDNAs showed that dolphin IL-1α and IL-1β clones contained open reading frames encoding 265 and 266 amino acids, respectively. Comparison of the deduced amino acid showed that dolphin IL-1α sequence shared 77, 77, 77, 74, 71, 65 and 57% similarity with the bovine, ovine, porcine, equine, feline, human and mouse IL-1α sequences, respectively. Similarly, the amino acid sequence showed that dolphin IL-1β shared 77, 77, 74, 69, 65, 64 and 63% similarity with the bovine, ovine, porcine, equine, feline, human and mouse IL-1β sequences, respectively. The relatedness of dolphin IL-1α and IL-1β were relatively distant with 21% amino acid homology.