Hypomagnesaemia can arise from a variety of causes but is particularly prevalent in cancer populations. This case report describes a patient with recurrent symptomatic hypomagnesaemia, on the background of advanced ovarian cancer and a high-output ileostomy, who was successfully managed on a daily continuous subcutaneous infusion of magnesium via a syringe pump. There is limited published information on the subcutaneous administration of magnesium and, to our knowledge, this is the first case to report its routine delivery over 24 hours in a syringe pump. This novel but effective approach for administering magnesium can be delivered in the community and can, therefore, prevent repeated hospital admissions for patients with recurrent symptomatic hypomagnesaemia who would otherwise need intravenous replacement., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)