Objectives: to ascertain the degree of acceptance, the perception of health benefits and the level of satisfaction in cancer patients who have undergone Reiki therapy.  
Material and methods: cross-sectional descriptive study, performed in the Bone Marrow Transplant and Haematology Unit of the Ramón y Cajal Hospital (Madrid) over the course of nine months (2008-2009), by means of a self-elaborated, self-administered questionnaire comprised of 38 questions regarding: sociodemographic variables, familiarity with complementary therapies and Reiki therapy.  
Results: all patients (n = 119) were offered the possibility of participating, with a 42% response rate (n = 50). 63,3% believed in the efficacy of complementary therapies. The most frequently experienced sensations were: feeling hot (65,8%), muscle relaxation (61,5%), sleepiness (31,6%), decreased anxiety (30%) and improved mood (30%), and also improved sleep (48,3%) and decreased pain (46,2%). 70,8% (n = 34) thought it was a very good idea to offer Reiki in the hospital, with 97,9% (n = 46) also believing it should be extended to other services/hospitals.   
Conclusions: cancer patients show a high degree of acceptance and satisfaction with Reiki therapy. The sensations experienced were: feeling hot, muscle relaxation, sleepiness, decreased anxiety and improved mood; as well as effects on symptoms related with the reason for admission into hospital (pain, anxiety and/or muscle tension and sleep pattern disturbances).