With the increasing cost of health care and the growing constraints made by third party payers, in-hospital time for preoperative teaching is quickly being reduced. Seventy-two patients attended preoperative instruction either as an inpatient the day before surgery or as an outpatient 4-8 days before surgery. Anxiety and knowledge levels were measured before and after class and the evening before surgery. No differences were found between the groups on a measure of anxiety levels. Both groups demonstrated a moderate anxiety level with no significant change over the testing period. Using the knowledge pretest as a covariate, repeated measures analysis of variance suggested the knowledge gained with the class was significantly greater for the outpatient group than the inpatient group (P = 0.018). There was also a significant positive relationship between the knowledge score and knowing someone who had cardiac surgery (t = 2.34, d.f. = 66, P = 0.022). The results suggest that it makes little difference whether patients receive information up to a week before surgery or just the day before; therefore, the more economical preadmission teaching may be the path of choice.