The freeze-intolerant insect, Choristoneura fumiferana (spruce budworm), produces multiple antifreeze protein (AFP) isoforms for protection during the overwintering nowreport the cloning ofAFPgenes frominsects; Afp-Lu1encodes a 9-kDa AFP isoform, andAfp-Iu1 encodes a 12-kDa AFP isoform. BothCfAFP genes have similar structures with a single 3- to intron inter-rupting the coding region.