The filarioid nematode Pelecitus fulicaeatrae (Diesing, 1861) is considered cold-hardy. Adults and microfilariae became motile when placed in saline at 22 C after having been removed from thawed carcasses of their host, the American coot (Fulica americana Gmelin) (Aves: Gruiformes). Adult nematodes from 5 of 12 carcasses became active as did microfilariae from 4 of 5 carcasses. Carcasses had been frozen at an undetermined temperature below 0 C for an initial 14 days and then at -21 to -24 for 100-159 days.