Fatty acid composition of larvae, pupae, and adults of the mud-dauber wasp, Sceliphron destillatorium Illiger 1807, as well as spiders obtained from its nests was investigated for the first time. All samples were obta- ined from mud nests of the wasp collected from the field. Adults of this insect feed on nectar of flowers but their larvae feed on spiders. Totally 15 fatty acids were identified and quantified by GC-FID in analyzed samples. The highest of all fatty acids is oleic acid which was found as: 43.87%, 42.43%, 48.69%, and 43.88% in larvae, pupae, adult, and the spiders respectively. Fatty acid compositions in larvae, pupae, and spiders were found close to each other. Alpha linolenic acid was determined in larva, pupa, and spider but not in adults, so it seems to be essential fatty acid for this wasp species. The data obtained are usable to reveal the relationship between fatty acid composition and nutrition or physiological events in insects.