This multicenter study was intended to validate the French version of the M. D. Anderson Symptom Inventory (MDASI-Fr) in French cancer patients (n=162) with solid tumors or hematological malignancies. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) was used as a part of the validation. Factor analysis showed three underlying constructs for symptom items: general symptoms (pain, fatigue, disturbed sleep, shortness of breath, drowsiness, dry mouth, and numbness or tingling items); emotional and cognitive components (distress, sadness, and remembering items); and a gastrointestinal component (nausea, vomiting, and lack of appetite items), with Cronbach's alphas of 0.79, 0.73, and 0.71, respectively. Convergent validity was established by comparing MDASI-Fr items with the EORTC QLQ-C30 scale and the Brief Pain Inventory (BPI). Overall, the 19-item MDASI-Fr score correlated well with the QLQ-C30 global health status, and the pain item of the MDASI-Fr was highly correlated with the short form of the BPI. The most prevalent symptoms were fatigue, distress, dry mouth, and pain. Twenty-five percent of patients reported moderate or severe pain (numeric rating scale >4 on 0-10 severity ratings). Physician ratings of global change on a second visit were significantly associated with changes in patient ratings on the MDASI-Fr, supporting the sensitivity of the measure. Symptoms interfered most with work and general activity. The MDASI-Fr is a valid and reliable tool for measuring symptom severity and interference in French cancer patients.