Introduction: Bone metastases are frequent complication of cancer and frequently cause pain. Indications for radiotherapy for bone metastases include pain, risk of pathologic fracture, and neurological complications arising from spinal cord compression, nerve root pain or cranial nerve root involvement.Aim of this study was to assess the clinical and biological effect of single fraction palliative radiotherapy in the form of single fraction versus multiple fractionated radiation therapy for patients with bone metastases from solid tumors.Patients and methods: Sixty patients were divided in to three groups: Group I had 30 Gy in ten fractions, group II had 20 Gy in five fractions and group III had single fraction of 8 Gy. Follow up of clinical effect in the form of pain response, mobility, analgesic use and performance status before treatment and every two weeks for six weeks. Biological response was assessed by follow up bone resorption marker DPD before and after six weeks of radiation therapy.Results: The study resulted in 42 responders to pain out of sixty patients and re-irradiation was needed in group II and III. The biological response was correlated with the clinical response in the three groups. And there was no significant difference between the use of single fraction and multiple fractionated radiation therapy in both clinical and biological response.Conclusion: The use of different fractionated schedules of radiation therapy among patients with painful bone metastases of solid tumors has no significant difference clinically or biologically and the use of bone resorption marker can be done as a predictor of outcome in these patients.