Chicken counterpart of interleukin-2 (chIL-2) is discovered recently which shows great potential in immunotherapy and immunoadjuvant applications. In view of its immunomodulating effects and involvement in disease resistant traits, this study compared the sequence relatedness and the genetic evolution of chIL-2 genes of local breeds with other geographical isolates. The chIL-2 genes from two Chinese local breeds (Xianju and Silky) and a commercial broiler breed (Avian) were amplified and cloned from Con A-stimulated chicken spleen lymphocytes. Sequence comparison revealed a similar genetic organization among the breeds with a coding region of 429 bases, a 5′-terminal untranslated region (UTR) with 17 nucleotides in length and an UTR with 285 nucleotides with five repetitive sequence of ATTTA at 3′-terminal. The deduced amino acid sequences were compared with strains Kestrel, Obese and SC Leghorn chickens from GenBank. Results showed that Xianju, Silky and Kestrel breeds shared an identical chIL-2 gene while the chIL-2 from Avian commercial broiler, Obese and SC Leghorn chickens was identical. In addition, a hypermutation region between residue 28 to 32 was identified. Phylogenetic analysis grouped Xianju, Silky and Kestrel, and Avian, Obese and SC into a separate group. Furthermore, a mutation from glutamic acid (E) to glycine (G) was found at the conserved residue 133 in Chinese official chicken breed-Silky chicken.