Aims: To describe patterns of treatment for those who receive more than one episode of megavoltage radiotherapy (retreatment) by cancer type for better service planning and benchmarking. Materials and methods: Institutional databases of all patients who received their first megavoltage radiotherapy for any type of cancer at the Liverpool and Macarthur Cancer Therapy Centres (LM), New South Wales, Australia, Royal Brisbane and Women's Hospital (RBWH), Queensland, Australia and Radiotherapeutic Institution Friesland (RIF), Leeuwarden, the Netherlands, over the period 1991-2009 were examined. Radiotherapy retreatment was defined as any radiotherapy episode, to any body site, after an initial episode of radiotherapy, for the same cancer diagnosis. The total retreatment rate was defined as the number of retreatment episodes of radiotherapy divided by the number of cases in the cohort. Results: In total, 62270 patients (RBWH 38581, LM 9654, RIF 14035) received 77762 episodes of radiotherapy, giving a total retreatment rate of 0.25; 52351 patients (84%) received only one episode of treatment and 9919 (16%) received two or more episodes of treatment. Overall retreatment rates for LM, RBWH and RIF were 0.24, 0.25 and 0.26, respectively. For the five most common cancer types treated, the median time between treatment episodes was longest for breast cancer (11.3 months), then head and neck cancer (9.7 months), colorectal cancer (7.2 months), prostate cancer (4.4 months) and lung cancer (4.1 months). Ninety-one per cent of all fractions were delivered in the first episode of treatment. Conclusions: The retreatment rate was very similar between the three facilities, suggesting agreement about the indications for retreatment.