Sixty-six guinea pigs with dental disease were presented to the University of Veterinary Medicine, Vienna, Austria, from 2006 to 2010. Almost all patients had a history of eating difficulties (95 per cent) and underwent clinical and oral examination as well as CT of the head. Findings on extra- and intraoral examination were asymmetric elongation (n=28) and symmetric bridging (n=24) of cheek teeth, obliquely worn incisors (n=17), palpable lower jaw swellings (n=13), exophthalmos (n=10) and incisor macrodontia (n=6). Eighty per cent of guinea pigs with exophthalmos showed ipsilateral periapical disease of the maxillary cheek teeth on CT. Ninety-two per cent of patients with palpable lower jaw swellings showed corresponding dental pathologies on CT. Periapical disease of incisors (n=11) and cheek teeth (n=32) were the most common findings on CT. All abnormally large incisors were found on oral examination and CT, but macrodontia of cheek teeth could only be visualised by CT. Deviation of the lower jaw evaluated in awake animals by visual inspection appeared to correlate with cheek teeth abnormalities. Results emphasise the importance of diagnostic imaging, in particular CT, in guinea pigs with dental disease in order to localise lesions and underlying aetiologies.