Performance status assessment, Karnofsky performance status (KPS), and Eastern Cooperative Oncology Group (ECOG) scales were performed in 100 consecutive patients independently by two physicians and by the patients themselves to evaluate the scales' validity and reliability. Findings of Kendall's correlation were highly significant between physicians (0.76 for KPS, 0.75 for ECOG) and between physicians and patients (0.65 for KPS, 0.59 for ECOG). The authors point out that patients' self evaluation could provide a valuable and reliable assessment.