Palynomorph assemblages dominated by dinoflagellate cysts are described from seventeen samples from the Rabot Member of the Santa Marta Formation at Ekelöf Point, eastern James Ross Island, Antarctic Peninsula. Although the assemblages are of relatively low diversity, the dinoflagellate cyst taxa recorded indicate a mid to late Campanian (Late Cretaceous) age. Changes in species diversity, dominance and gonyaulacacean ratio suggest a gradually reducing distance from shore during deposition, with a return to more offshore conditions towards the section top. A new species of dinoflagellate cyst, Isabelidinium papillum, is described.