The parasitoid complex of white-spotted pinion Cosmia diffinis (Linnaeus, 1767) larvae (Lepidoptera: Noctuidae) feeding on Ulmus minor in Edirne was studied during the two-year period of 2007–2008. The determined parasitoids were Meteorus colon (Haliday, 1835) and Meteorus rufus (DeGeer, 1778) from Braconidae; Gelis areator (Panzer, 1804), Itoplectis clavicornis (Thomson, 1889) and Phobocampe lymantriae Gupta, 1983 from Ichneumonidae; Brachymeria secundaria (Ruschka, 1922) from Chalcididae; Euplectrus liparidis Ferrière, 1941 from Eulophidae and members of Tachinidae. We report here a new host-parasitoid relationship of C. diffinis with M. colon, M. rufus, I. clavicornis, P. lymantriae, and E. liparidis. The hyperparasitism of G. areator and B. secundaria on parasitoid Meteorus species of Cosmia diffinis is also reported. In addition, M. colon, I. clavicornis, G. areator, P. lymantriae and E. liparidis were determined as new records for Turkey.