High spatial resolution MRI of the rectum is an accurate method of staging rectal cancer. The technique requires attention to detail so that correct planes and scan parameters are used to obtain the best images. A detailed understanding of the pathological features of these tumours is required for image interpretation so that prognostic information beyond the basic T and N staging of the tumour can be obtained. Use of standardized criteria for reporting is reproducible in the multicentre setting and pre-operative multidisciplinary discussion of the MRI features increases the number of operations performed with tumour-free resection margins.