İstanbul Islands are generally thought to consist of four large islands, but there are also five smaller islands. With this study, the Staphylinidae fauna of the İstanbul Islands (nine islands in total) was determined for the first time. In 2023, field studies were conducted on nine islands (Büyükada, Heybeliada, Burgazada, Kınalıada, Sedefada, Sivriada, Yassıada, Kaşık Island and Tavşan Island) and Staphylinidae species were collected. Twenty-three species in five subfamilies were identified, and four of these species (Aleochara (Emplenota) albopila (Mulsant and Rey, 1851), Atheta amplicollis (Mulsant and Rey, 1873), Halobrecta flavipes Thomson, 1861, Oligota muensteri latior Kapp, 2019) are new records for Turkey. In addition, ten species were recorded for the first time from the Marmara Region. Nine species are new records for İstanbul.