The clinical diagnosis of stomatological disease may indicate its cause and prognosis; however, it says little about the resulting level of impairment from the patient's perspective. The primary objective of this study was to test whether patients attending an outpatient oral medicine clinic would have worse oral health related quality of life (OHR-QoL) compared with the general population. In addition, we aimed to assess whether anxiety or depression could be predicted by OHR-QoL and to explore the relationship between clinical diagnoses, OHR-QoL and anxiety/depression. Data were collected from patients (n = 97) through face-to-face interviews using the Oral Health Impact Profile Short form (OHIP-14) to measure OHR-QoL, the Hospital Anxiety and Depression Scale (HADS) for psychiatric morbidity, and a visual analogue scale for self-rated general health. Age- and sex-matched controls (n = 388) were provided from a normative data set collected in a UK national survey in 1998. Participants had significantly lower OHR-QoL scores than the general population on all domains and overall OHR-QoL scores. Of the variance in anxiety, 55% was predicted by general health ratings and OHR-QoL domains of ‘psychological discomfort’ and ‘psychological disability’. Of the variance in depression, 54% was predicted by general health ratings and OHR-QoL domains of ‘functional limitation’ and ‘social disability’. Patient centred, routine assessment of OHR-QoL provides an additional dimension that may help to improve awareness of the impact of disease on the individual's life and enhance the clinical decision-making process.