Seven brands of commercial baler twine used for tying bales of hay or straw were tested for resistance to damage by mice, Peromyscus spp. and Microtus spp.; crickets, Gryllus spp., and rot. All 7 brands were cut by laboratory mice, house mice, and field mice in the laboratory tests, whereas in field tests only 3 brands were cut. Neither rot nor field crickets damaged the test twines.