A study investigated the influence of sex on perceived credibility. It was predicted that males would have more credibility than females, and that males and females would respond differently to the question of having more credibility if they were of the opposite sex. A series of research questions concerning both the similarity of sex of the stimulus and the receiver and the influence of the sex of the interviewer on the subject were posed; and the variables of competence, trustworthiness, dynamism, and coorientation were examined. Subjects were 145 men and 160 women randomly selected from the local telephone directory of a midwestern university town. Each subject was interviewed by phone by a male or female interviewer. The results indicated that (1) men were perceived to have more credibility than women; (2) men felt they would have less credibility if they were women, and women felt they would have more credibility if they were men; (3) subjects responding to female interviewers selected males as being more credible at a significantly higher level than they selected females; (4) men were perceived to be more competent than women, but women were perceived to be more trustworthy than men; (5) men were perceived to be higher in dynamism than women, but women were perceived to be higher in coorientation than men; and (6) both men and women perceived that they would have more credibility with persons of the same sex than with persons of the opposite sex. (HTH)