We studied attitudes of health professionals toward life-sustaining treatment. A patient management questionnaire sent to staff physicians and nurses in 183 Oregon nursing homes consisted of eight patient sketches which varied age, mental status, and enjoyment of life. Respondents were asked whether they would favor tube-feeding to correct malnutrition in each case. Nurses showed higher preferences for tube-feeding than did physicians (P = .05). For both professions, patient happiness was the strongest and most significant (P less than .0001) influence upon preferences for tube-feeding. Both professions also showed a significant (P less than .001) tendency to give younger patients higher preferences for tube-feeding. Physicians showed a significant (P less than .001) influence of patient mental status upon preferences, while patient mental status did not affect nurses' preferences. Identifiable clinical factors appear to influence attitudes of physicians and nurses toward tube-feeding decisions.