The study is based on the radiolarian assemblages of five radiolarite outcrops and two boreholes from the Darnó and Szarvaskő Complex, Hungary, and three radiolarite sections from the western Vardar Ophiolitic Unit in Serbia. These investigated sections belong to a Mesozoic volcano-sedimentary mélange belt that can be followed from the Hellenides, through the Dinarides to the western Carpathians. Samples from radiolarite localities in the Darnó and Szarvaskő Complex contain a mixture of Middle Triassic (Illyrian to Longobardian) and Upper Triassic (Carnian) fairly poorly preserved radiolarian assemblages. Radiolarite samples from the western Vardar Ophiolitic Unit (Gostilje, Krš Gradac and Bukovi) yielded poorly preserved Upper Triassic (Carnian-?Norian) radiolarians. Co-occurrences of Middle and Upper Triassic radiolarian specimens in Darnó and Szarvaskő Complex suggest resedimentation during the Carnian or later. One new radiolarian species (Baumgartneria szarvaskoensis n. sp.) is described herein from the Darnó and Szarvaskő Complex.