A randomized trial comparing between two fractionation schedules in the treatment ofmetastatic bone pain. Purpose : To compare the efficacy and side effects of two different dose fractionationschedules, which are equal in biologically effective dose ( BED ) in the management of painful bone metastases. Materials and Methods : In a prospective trial, 95 patients with a total 124 sites wererandomized to receive either 30 Gy given in ten fractions, daily ( BED 32 Gy10) or 17 Gy given in two fractions, every other day (BED 30 Gy10). The primary tumor was in 28%, 23%,16%, 11% and 22 % of patients with  breast, lung ,prostate, colorectal, and other cancer, respectively. Outcome measures were pain relief, as measured by the visual analogue scale (VAS), patients' assessment of treatment and analgesic consumption, especially in the first month.  Results : A total of 114 treatment sites were evaluable for response. The two groups did not differ with respect to age, sex, primary tumor, metastasis location, performance status, degree of pain and analgesic consumption. The treatment was completed as planned in 96 % of patients. The degree of pain relief did not differ between the two treatment groups. In the first month, the overall response rateswere 94% in two treatment group. Nevertheless, in arm 2 achieved significantly faster relieve on the pain symptom than arm 1 (p=0.007). There was neither any significant difference in the duration of pain relief nor the need of reirradiation. There was no toxicity in the two groups. Conclusions : This preliminary randomized study showed that 30 Gy given in ten fractions, daily ,was as effective as 17 Gy given in two fractions, every other day, in the relieving pain from bone metastases.