Little attention has been given to the preparation of the patient's family prior to surgery, even though nurses' clinical experience suggests that family members are often more anxious than the patient. This study explored the knowledge and anxiety of spouses and significant others of patients preparing for cardiac surgery. The subjects were selected by convenience from a preoperative class offered at the hospital where surgery was to occur. Before and after the class, the subjects completed a cardiac-surgery knowledge test and an anxiety test. The significant others were significantly more anxious than the patients prior to the class. The anxiety level of significant others was significantly reduced after the class. There were no statistically significant differences between patients and significant others on the cardiac-surgery knowledge test. These results suggest that significant others may benefit from preoperative instruction.