Presence of tumour at the resection margin following primary surgical treatment for squamous cell carcinoma of the head and neck is thought to adversely affect prognosis. To confirm this we performed a review of 478 patients treated by primary surgery for squamous cell carcinoma of the head and neck and sub-divided them into those exhibiting positive margins and those with negative margins following resection. Uni-variate and multi-variate statistical methods were used to analyse survival figures and a variety of parameters associated with the presence of positive resection margins. We found 5-year survival was decreased if resection margins were found to be positive (P < 0.025). The presence of positive resection margins was also significantly associated with time to tumour recurrence (P < 0.001) and survival with nodal recurrence (P < 0.001). Other factors which were significantly associated with survival using Cox's multi-variate analysis were site of tumour (P < 0.005), nodal extracapsular rupture (P < 0.05), histology (P < 0.05) and pathological T-stage (P < 0.05). Uni-variate analysis revealed no significant associations between the presence of positive margins and the patient's age, sex, tumour site, degree of tumour differentiation, and nodal status, though using multiple logistic regression, the general condition of the patient (P < 0.01) and the tumour site P < 0.05) were significantly related. The results support the concept that every effort should be made to obtain negative resection margins when undertaking primary ablative surgery for squamous cell carcinoma of the head and neck.