Recent randomised studies have reported that single fraction radiotherapy is as effective as multifraction radiotherapy in relieving pain caused by bone metastasis. However, there are concerns about the higher re-treatment rates and the efficacy of preventing future complications, such as pathological fracture and spinal cord compression, by single fraction radiotherapy. A systematic review of randomised studies, examining the effectiveness of single fraction radiotherapy versus multiple fraction radiotherapy for metastatic bone pain relief and prevention of bone complications, was conducted to help answer this controversy. Randomised studies comparing single fraction radiotherapy with multifraction radiotherapy on metastatic bone pain were identified. The analyses were performed using intention-to-treat principle. The results were pooled using meta-analysis to estimate the effect of treatment on pain response, re-treatment rate, pathological fracture rate and spinal cord compression rate. Twelve trials involving 3621 sites were included in the meta-analysis. The overall pain-response rates for single fraction radiotherapy and multifraction radiotherapy were 60% (1080/1814) and 59% (1060/1807), respectively, giving an odds ratio (OR) of 1.03 (95% confidence interval [CI] 0.90-1.19), indicating no difference between the two radiotherapy schedules. There was also no difference in complete pain response rates for single fraction radiotherapy (34% [508/1476]) and multifraction radiotherapy (32% [475/1473]), with an OR of 1.10 (950% CI 0.94-1.30). Patients treated by single fraction radiotherapy had a higher re-treatment rate, with 21.5% (267/1240) requiring re-treatment compared with 7.4% (91/1236) of patients in the multifraction radiotherapy arm (OR 3.44 [95% CI 2.67-4.43]). The pathological fracture rate was also higher in single fraction radiotherapy arm patients. Three per cent (37/1240) of patients treated by single fraction radiotherapy developed pathological fracture compared with 1.6% (20/1236) for those treated by multifraction radiotherapy (OR 1.82 [95% CI 1.06-3.11]). The spinal cord compression rates were similar for both arms (OR 1.41 [95% CI 0.72-2.75]). Single fraction radiotherapy was as effective as multifraction radiotherapy in relieving metastatic bone pain. However, the re-treatment rate and pathological fracture rate were higher after single fraction radiotherapy. Studies with quality of life and health economic end points are warranted to find out the optimal treatment option.