Aims: To identify the adverse effects of third molar surgery having the greatest impact on patients' perceived quality of life; and to compare the rankings between patients, dental practitioners (GDPs) and hospital consultants. Method: Seven adverse effects were identified after interviewing 20 patients. A questionnaire was sent to 120 patients whose third molars had been removed and 121 dental surgeons (100 GDPs and 21 consultants in oral and maxillofacial surgery). Results: Response rates for patients, GDPs and consultants were 72.5%, 92% and 76.2% respectively. Patients ranked highest the effects on eating, while dental surgeons ranked 'pain' the highest. The mean rankings of consultants and patients generally showed a closer agreement, than with GDPs. However, no statistically significant differences were detected between the mean rankings of GDPs and consultants. Conclusions: Dental surgeons' perceptions of the impact of third molar surgery on their patients' quality of life show statistically significant differences from those of patients for four of the seven parameters assessed. Clinicians should consider mentioning the effects on ability to eat when obtaining informed consent, since patients would appear to rank this an important side effect.