Evaluated the psychometric properties of the Cancer Inventory of Problem Situations (CIPS), a cancer-specific survey instrument designed to assess day-to-day problems and rehabilitation needs of cancer patients. A heterogeneous group of 479 cancer patients participated in the research. The substructure of the CIPS was investigated using factor-analytic techniques. The CIPS was factored into 31 clinically useful subscales. Further analyses led to five higher order factors representing the physical, psychosocial, medical interaction, marital, and sexual problem areas characteristic of cancer and its treatment. Internal consistency of all the scales was high (mean alpha = .81). The test-retest reliability and validity of the instrument were also studied in a sample of 120 patients. Analyses of items, subscales, higher order factors, and total CIPS scores suggest excellent reliability. The pattern of correlations of the CIPS with other measures (psychological distress; physical, marital, and sexual functioning; and quality of life) provided preliminary evidence of concurrent, discriminant, and convergent validity. The CIPS appears to have sound psychometric properties and fills an important gap in the assessment of cancer patients for both clinical and research purposes.