Background: This study aimed to create and validate a survival score for patients with metastatic spinal cord compression (MSCC) from cancer of unknown primary. Patients and methods: The entire cohort (n = 182) was divided into a test group (n = 91) and a validation group (n = 91). In the test group, eight pretreatment factors including age, gender, Eastern Cooperative Oncology Group performance status (ECOG-PS), number of involved vertebrae, ambulatory status, other bone metastases, visceral metastases, and time of developing motor deficits were retrospectively analyzed. Results: The score included the prognostic factors that were significant for survival in the multivariate analysis (ECOG-PS, ambulatory status, visceral metastases, time of developing motor deficits). The score for each factor was determined by dividing the 6-month survival rate by 10. Prognostic scores represented the sum of the scores for the four factors and ranged from 5 to 20 points. The 6-month survival rates were 5% for < 14 points, 41% for 14-16 points, and 92% for > 16 points (p < 0.001). In the validation group, the 6-month survival rates were 7%, 38%, and 91% (p < 0.001). Conclusion: This survival score can be considered valid and reproducible, since the survival rates of the validation group were comparable to those of the test group. This score can help when selecting the individual treatment and when counseling patients and relatives.