Post mortem examination of a young fallow deer (Dama dama) revealed a severe purulent and necrotizing glossitis as well as a multifocal necrotizing and ulcerative rumenitis and typhlitis. The animal was cachectic. Mannheimia (M.) sp. was isolated from the tongue lesions and identified as M. granulomatis by MALDI-TOF MS and 16S rRNA sequencing. Mycosis and BVDV infection were excluded. Few publications are dealing with similar macroscopic findings associated with the isolation of M. granulomatis in cattle and roe deer. Therefore, M. granulomatis should also be taken into consideration when such lesions occur in other ruminants. Based on our findings in case of gross pathological lesions of the tongue of ruminants a Mannheimia granulomatis-infection should be investigated as well as the possible role of Fusobacterium necrophorum, Actinobacillus lignieresii or Actinomyces bovis.