The famous Iceman ‘Ötzi’ (South Tyrol Museum of Archaeology, Bolzano, Italy), a Neolithic human ice mummy, offers a unique opportunity to study evolutionary aspects of oral disease. The aim of this study was to assess, for the very first time, his oral cavity, which surprisingly had never been examined systematically. Based on several computed tomography (CT) scans from 1991 onwards and on macroscopic investigation, only a few findings, such as a central maxillary diastema, heavy abrasions, and missing wisdom teeth, were known. We re-evaluated the latest CT scans from 2005 and found various oral pathologies. In line with the increase of tooth decay in the Neolithic – because of diet change in this historic transition phase – several carious lesions were found, one of which penetrated into the dental pulp. In accordance with the Iceman's troubled life, as several injuries on his body and his violent death attest, mechanical trauma of one of his upper front teeth is evident. Finally, the poor periodontal condition of the Iceman's dentition (e.g. loss of alveolar bone), indicative of periodontitis, was assessed. These oral pathological findings in the Iceman's dentition provide a unique glimpse into the evolutionary history of oral conditions.