Qigong is a mind-body integrative exercise or intervention from traditional Chinese medicine used to prevent and cure ailments, to improve health and energy levels through regular practice. The aim of this systematic review is to summarize and critically evaluate the effectiveness of qigong used as a stand-alone or additional therapy in cancer care. We have searched the literature using the following databases from their respective inceptions through November 2006: MEDLINE, AMED, British Nursing Index, CINAHL, EMBASE, PsycInfo, The Cochrane Library 2006, Issue 4, four Korean Medical Databases, Qigong and Energy Medicine Database from Qigong Institute and four Chinese Databases. Randomised and non-randomised clinical trials including patients with cancer or past experience of cancer receiving single or combined qigong interventions were included. All clinical endpoints were considered. The methodological quality of the trials was assessed using the Jadad score. Nine studies met our inclusion criteria (four were randomised trials and five were non-randomised studies). Eight of these trials tested internal qigong and one trial did not reported details. The methodological quality of these studies varies greatly and was generally poor. All trials related to palliative/supportive cancer care and none to qigong as a curative treatment. Two trials suggested effectiveness in prolonging life of cancer patients and one failed to do so. We conclude that the effectiveness of qigong in cancer care is not yet supported by the evidence from rigorous clinical trials.