This   paper   focuses   on   the   ‘design’   of   emotional wellbeing  in  a  cancer  care  service  system.  There  is little  or  no  scholarly  understanding  of  the  concept  of emotion  in  service  systems  discourse.  Yet,  emotion  is often referred to in service systems research; scholars have   pointed   out   the   need   to   create   long-term emotional  bonds  with    customers,    for    example. However, little or no attempt has been made to define or   understand  in  detail  the complex   concept   of emotion.  To  address  this  deficiency,  we  draw  on psychology and social theory to construct a theoretical framework  of  emotion  and  put  it  to  work  in  an empirical case study of a Maggie’s Centre in London. The questions addressed are - how do designers interpret, understand, and transform user emotion(al wellbeing). Put another way, how is emotional wellbeing ‘designed’ in a service system?