In order to characterize the T helper 1 (Th1) cytokines of llama, we have cloned several llama cytokine genes and compared them to those of other mammalian species. The cDNAs encoding for interleukin (IL)-2, interferon (IFN), IL-12p35 and IL-12p40 were amplified using specific primers designed from reported sequences of bovine cytokine genes. The cDNAs for llama IL-2, IFN-, IL-12 p35 and IL-12p40 were found to be 465, 501, 669 or 993 bp in length, with open reading frames encoding 154, 166, 222 or 330 amino acids, respectively. Homology analyses of nucleotide and deduced amino sequences of llama IL-2, IFN-, IL-12p35 and IL-12p40 and phylogenetic analysis based on their nucleotide sequences indicated the close relationship in these cytokine genes between llama and eutherian mammalian order Artiodactyla, which includes pig and cattle.