The objective of this systematic review was to identify quality trials that use sham radiotherapy in their design and review them to determine its potential value. The Cochrane Library, Pubmed and a Reference Search served as data sources. Trials were included if they met a minimum quality score of 3 on a validated assessment instrument (which assesses randomization, control and blinding) and if they compared sham radiotherapy to active treatment. External beam therapy and brachytherapy trials were considered. Twenty-six trials were identified, collectively including 2663 participants in the period of 1970-2004. All the trials studied the value of radiotherapy for treatment or prevention of benign diseases, including multiple sclerosis, coronary artery restenosis, age-related macular degeneration and Graves' ophthalmopathy. There were no trials relating to the use of radiotherapy in the treatment of malignancy. This review showed that it is possible to carry out sham radiotherapy with due regard for ethical concerns, with effective blinding and high levels of patient acceptance. Large sample sizes with multicentre trial designs were achievable. Although the statistical philosophy for using sham radiotherapy in trials is legitimate, it is no longer routinely used.