Mastocytosis is a rare disorder with serious anaesthetic implications. Anaesthetic management is hazardous since trauma, stress, extremes of temperature and drugs may precipitate intra-operative mast cell degranulation. Release of histamine and other mast cell mediators can lead to profound cardiovascular collapse and even death. We present a case report of a patient with mastocytosis who suffered cardiac arrest during anaesthesia. Anaphylactoid/anaphylactic shock may be delayed and lack supporting signs of histamine release such as cutaneous flushing and bronchospasm.