The eulophid parasitoids (Hymenoptera: Eulophidae) of Cameraria ohridella Deschka and Dimic (Lepidoptera: Gracillariidae) on horse chestnuts (Aesculus hippocastanum L.) in Istanbul were determined for the first time. Horse chestnut leaves infested with leafminers were collected in 2008 and adult parasitoids were obtained in emergence cages in the laboratory. A total of 10 eulophid parasitoid species were identified, 5 of which, namely Cirrospilus viticola (Rondani), Pnigalio mediterraneus (Ferriere and Delucchi), Minotetrastichus frontalis (Nees), M. platanellus (Mercet), and Closterocerus trifasciatus Westwood, were recorded for the first time in Turkey. All of the identified parasitoid species have already been reported as parasitoids of C. ohridella in countries of Europe. Therefore, our findings are in accordance with these studies carried out in European countries.