Background Elderly patients with lung cancer need personalized treatment in palliative situations such as metastatic epidural spinal cord compression (MESCC). It is crucial to know a patient's survival prognosis to be able to provide optimal and individualized care. Therefore, a prognostic instrument enabling physicians to estimate a patient's survival time is required. We created such an instrument in the present study. Patients and Methods The data from 201 elderly patients with lung cancer irradiated for MESCC were retrospectively evaluated. The radiation regimen used plus 10 factors were analyzed for associations with survival, including age, gender, histologic features, performance status, interval from lung cancer diagnosis until irradiation of MESCC, interval to developing motor weakness before irradiation, number of affected vertebrae, visceral metastases, other bone metastases, and the ability to walk before irradiation. The factors significant on multivariate analysis were included in the predictive instrument. The factor scores were obtained by dividing the 6-month survival rate by 10, and the patient scores were determined from the sum of the factor scores. Results Performance status (P =.003), interval to developing motor weakness (P =.006), visceral metastases (P <.001), and the ability to walk (P =.002) were associated with survival. Taking into account the 6-month survival rates of these factors, the patient scores ranged from 5 to 19 points. Thus, 4 groups were designated: those with 5 to 10 points (n = 95), 11 to 13 points (n = 46), 14 to 16 points (n = 33), and 18 to 19 points (n = 27). The corresponding 6-month survival rates were 4%, 26%, 58%, and 81% (P <.001). The corresponding median survival times were 2, 4, 7, and 10 months. Conclusion This new instrument will enable physicians to predict the survival prognosis of elderly patients with lung cancer-related MESCC, facilitating individualized treatment care.