In order to allay concerns about using simulators as opposed to real mothers for teaching and evaluating interviewing skills, a study was designed to test for differences in students' approaches when interviewing simulated and real mothers. Three mothers were trained to give their own children's histories consistently and two mothers trained to simulate a history. Thirty third-year medical students conducted two interviews which were audiotaped. Students were told the nature of the study and whether the mother was real or simulated. One half of the time the mothers were presented as simulators and one half of the time the simulators were presented as mothers. The variable of order was controlled. An objective checklist containing 70 to 80 bits of organic and personal data per case and an interaction analysis (with an average of 285 interactions per interview) were utilized to measure the content material gathered and the approach used by the students. The data were analyzed using an analysis of variance (ANOVA) technique. All but 1 of the 55 null hypotheses were accepted, i.e., no significant differences were found. The Use of Simulation for Teaching and Evaluating Interviewing Skills Provides a Valid Experience.