Interventional magnetic resonance units give the surgeon the potential to use intraoperative imaging to guide the surgical procedure. The advantages of magnetic resonance (MR) over other intraoperative imaging modalities include excellent soft tissue resolution, lack of ionizing radiation and the ability to reconstruct images in any desired plane. Postulated advantages include the ability to confirm adequate tumour resection, reduction in procedure magnitude and complication rate, shortened inpatient stay and the development of novel minimally invasive techniques including the use of thermal energy to destroy lesions. Fully MR compatible anaesthetic and patient monitoring equipment is available. However, before the MR-guided minimally invasive surgery can become a reality, much work is required in the assessment and development of MR compatible surgical instrumentation and equipment. This review describes the testing and development of instruments and equipment for MR image-guided surgery that we have undertaken. We describe the techniques we employ for open and minimal access surgery within this unique environment. The difficulties of operating within such an environment and the safety issues that this engenders are discussed. The current applications of intraoperative MR in the main surgical specialities are reviewed, and possible future areas of development for MR-guided minimally invasive surgery described.