In October 2004, a free-living Stock Dove (Columba oenas) was found infected with Trichomonas spp. in the district of Soest, North Rhine- Westphalia, Germany. A huge buccal nodular lesion caused an occlusion of the esophagus and an external swelling. The bone of the mandibula was already softened and nearly solubilised. The microscopical examination of a wet swab sample from the carcass detected Trichomonas spp. in huge numbers. The morphological diagnosis of the flagellate revealed T. gallinae. Although trichomonosis is well described for several other columbid species around the world, this is probably the first described case of a trichomonosis in a free- living Stock Dove. The possible prevalence in the dove population is discussed.