Over 400 cancer patients were given the Illness Distress Scale (IDS), a brief measure of the physical and emotional distress related to serious illness. Physical manifestations of the disease proved to be the source of greatest discomfort among these patients. Greater distress was reported by younger patients and by those who were unmarried. Also, patients with more advanced disease scored higher on the scale. The IDS appeared to measure four dimensions of distress related to the experience of illness, including loss of meaning, physical disease, medical treatment and social isolation. Scores on the instrument correlated highly with a measure of depression, the Beck Depression Inventory. The IDS appears to be a reliable and valid measure of distress associated with serious illness.