A juvenile Cinereous Vulture (Aegypius monachus) fledgling was found disorientated on the roof of a building in Madrid City, Spain, in October 2016. A veterinary examination revealed multiple plaques distributed throughout the oropharyngeal cavity. Lesions were located under the tongue and at the choanal slit, hard palate, and esophagus opening and ranged from 2 to 7 mm, coalescing in areas up to 2 cm, with a yellowish color of the surface. Motile trichomonad trophozoites were detected in fresh wet mount smears from the lesions. Sequence analysis of the internal transcribed spacer (ITS)1/5.8S/ITS2 and small subunit ribosomal RNA confirmed that Trichomonas gypaetinii was the etiologic agent. Microbiologic cultures did not reveal any pathogenic bacteria or fungi. The animal recovered successfully after treatment with metronidazole and trimethoprim-sulfamethoxazole and was later released in a suitable habitat. Avian trichomonosis lesions caused by T. gypaetinii have not been reported.