The aim of this retrospective analysis was to determine the prognostic value of the time of developing motor deficits before radiotherapy (RT) and to confirm our preliminary results by achieving statistical significance. Of 529 patients receiving spinal irradiation (1994-1998) 131 fulfilled the selection criteria. Three groups were formed according to time of developing motor deficits: 1-7 days (n = 51), 8-14 days (40),114 days (40). Motor function was graded before, 2 weeks and 3 months after RT. After 2 weeks, patients developing motor deficits for 114 days showed improvement more often than patients of the other groups (65 versus 32.5 and 4%, p!0.001). After 3 months results were comparable (p!0.001). A slower development of motor deficits predicts a better functional outcome. Time of developing motor deficits before RT is a relevant prognostic factor in metastatic spinal cord compression.