To promote the inclusion of quality of life (QOL) end-points in clinical research on cancer, the National Cancer Institute (USA) sponsored a workshop on QOL assessment in cancer clinical trials in July, 1990. Experts in clinical trials and QOL research formed four working groups to identify current areas of cancer treatment in which QOL end-points are most important; to discuss methodologic problems in QOL assessment; to address common problems in implementing clinical studies with QOL end-points; and to consider statistical issues in design, implementation, and data analysis. Recommendations made by the working groups are summarized in this paper.