The purpose of this study was to develop an instrument for measuring the quality of life of cancer patients. Quality of life was measured with 14 linear analogue scale items concerning general physical condition, normal activities, and personal attitudes on general quality of life. The tool was tested with four subject groups: oncology outpatients receiving chemotherapy (43) or radiation therapy (39), oncology inpatients receiving chemotherapy (48), and nonpatient volunteers (48). Test-retest reliability coefficients for these samples ranged from r = .11 to .97, with 52 of the 56 possible r's greater than .60, p less than .01; internal consistency was .88, p less than .01. Construct and discriminant validity were indicated, while concurrent validity between quality of life scores and physician estimates of Karnofsky ratings, prognosis, and quality of life were poor.