Ninety-six patients with a ureteral calculus participated in a study whose purpose was to identify those subjects who would benefit from participation in clinical decision-making. Forty-two of the subjects (the experimental group) were given information about two alternative treatments, Extra Corporeal Shock Wave Lithotripsy (ESWL) and ureteroscopy, and were asked to choose which therapy they preferred. Fifty-four subjects (the control group) were not given information, not allowed to choose, and were treated according to the physician's decision. Subjects' level of anxiety was compared within each group on three occasions: before meeting with the physician, immediately afterwards and upon hospitalization for treatment of the stone. Patients perception of receipt of information and participation in clinical decision-making, coping style, educational level, and knowledge about treatment alternatives were also measured. A statistically significant decrease in anxiety after meeting with the urologist was found among patients who were not asked to participate in the decision-making process and among patients who perceived that they had received information. A decrease in anxiety after meeting with the physician was also found among patients who, according to their own perception, did not participate in decision-making. Patients' educational level and coping style were related to their anxiety. A decline in anxiety was found among those with a lower educational level who perceived that they had received information and among higher educated patients who perceived that they participated in clinical decision-making. Anxiety also declined among patients with a passive coping style who perceived that they had received information or had participated in the decision-making process. The results emphasize the need to tailor the therapeutic approach to patient characteristics.