Object: We validated the adequacy of using Palliative Prognostic Index (PPI) as a prognostic method for medical oncology patients. Method: PPI was measured for patients with advanced cancer admitted to our department from May 2015 to June 2016.Result: There were 45 patients analyzed. When classified into three groups according to the score of PPI, there was a tendency for survival curves to separate according to risk. Especially, there was a statistical difference in survival time between the high-risk group (PPI: ≥6.5) and the low-risk group (PPI: ≤4.0) (median survival time: 11 days vs 39 days, p=0.0048, HR: 2.75, 95%CI: 1.32-5.84). Prognostic accuracy of the PPI≥6.5 is similar to other reports. There is no difference in the accuracy of the prognostic prediction depending on the period from drug therapy to PPI evaluation. It was suggested that the influence of drug therapy on PPI evaluation is small. Discussion: We showed that it is appropriate to use PPI for the prognostic prediction of medical oncology patients.