A multi-institutional prospective study for the analysis of prognostic factors for patients with osseous metastasis was performed. From February 1986 through June 1988, a total of 216 patients were included in this study. Cox's regression model made it clear that the most significant overall prognostic factor was primary site (p = 0.0002). In the lung cancer group, performance status (p = 0.0036) and metastasis of organs than bone (p = 0.0105) were also significant prognostic factors. In the breast cancer group, no significant factors were obtained. In the hepatoma group, the values for alkaline phosphatase (ALP) (p = 0.0021), lactate dehydrogenase (LDH) (p = 0.0195), and sex (p = 0.0264) proved significant. In the group of other cases, the most significant prognostic factor was the value for urinary hydroxyproline/creatinine ratio (p = 0.0001), followed by the pain score of RTOG (p = 0.0018). These factors and actual survival periods obtained in this study will be useful for the future stratification of patients for individualized optimal radiation schedules.