AIMS Positive microscopic margins after major cancer surgery adversely affect prognosis. We questioned whether the benefit of a multimodal approach in oesophageal carcinoma is due to reduced resection margin involvement and whether multimodal therapy alters the disease course when margins are involved. METHODS Pathology specimens of 212 patients, treated with either multimodal therapy or surgery alone, were re-reviewed to assess margin involvement by tumour. Margin status was compared with recurrence and survival data. RESULTS Margin involvement was decreased with multimodal therapy (16 of 103 patients) vs surgery (33 of 109 patients), associated with reduced tumour recurrence and a significant survival advantage. However, even with involved margins, multimodal therapy had lower recurrence vs surgery and a small survival benefit. CONCLUSIONS Multimodal therapy significantly reduces margin involvement. The benefit of multimodal therapy remains highly significant for patients with clear margins. This study confirms for oesophageal carcinoma the value of an aggressive surgical approach in achieving negative resection margins.