Assessing cancer-related symptoms requires a brief, reliable, valid, and culturally adapted symptom screening tool. In the Philippines, cancer patients (n=206) and community-dwelling adults (n=170) participated in a cross-sectional validation study of the Filipino version of the M. D. Anderson Symptom Inventory (MDASI-F). Both exploratory factor analysis and hierarchical cluster analysis revealed two underlying symptom severity constructs--general and gastrointestinal symptoms--consistent with the English, Japanese, and Chinese versions of the MDASI. Cronbach alpha coefficients of 0.79 and 0.77, respectively, demonstrated acceptable internal consistency for the two factors. Known-group validity was confirmed by significant differences on MDASI-F items by performance status (P<0.01 or P<0.001). Fatigue, sadness, distress, and pain were significant predictors of symptom interference. Cancer patients reported significantly greater symptom severity on multiple items than did the community sample. The MDASI-F is reliable and valid for evaluating cancer-related symptoms and their impact on Filipino cancer patients.