Rectal cancer is a common malignancy with a highly variable outcome. Local recurrence is dependent upon tumour stage and surgical technique. The role of pre-operative imaging is to determine which patients may be safely managed by surgery alone and which need additional therapy in order to facilitate surgery and improve outcome. This decision depends on the distinction between those with early and advanced disease. While trans-rectal ultrasound has traditionally been used to answer this question, a role for magnetic resonance imaging (MRI) is increasingly argued. This review will focus on the treatment options for rectal cancer and the clinical questions that subsequently arise for the radiologist to answer.