This paper reviews a range of issues related to the assessment of subjective response and quality of life in prostate cancer clinical research. With regard to subjective response criteria, the Karnofsky performance status scale and the subjective components of the World Health Organization acute and subacute toxicity scales appear to hold certain advantages over competing measurement systems. Nevertheless, the available evidence suggests that further developmental work is needed to improve the precision of these instruments. In the area of quality of life assessment, there does not appear to be a clear choice among the array of available measures. Although there are several promising instruments, none has undergone sufficient field testing to justify widespread adoption in clinical research settings. A number of suggestions are offered to facilitate further development in quality of life instrumentation and research implementation.