Twenty-nine male and 37 female adults served as mock jurors in a simulated criminal trial in which the amount of preview offered in both the prosecution's and defense's opening statements was factorially varied. It was found that the effects upon verdicts of guilt of the amount of preview in either side's opening statement depended on that in the other side's opening statement. Extensive prosecution opening statements led to more guilty verdicts only when the de fense's opening statement was also extensive; when the defense's opening statement was brief, participants tended to find the defendant guilty regardless of the amount of preview in the prosecution's opening statement. Extensive opening statements from the defense led to more not-guilty verdicts only when the prosecution's opening statement was brief. Results from a series of mid-trial measures indicated that opening statements predisposed jurors to favor one side or the other very early in the trial, and that jurors tended to maintain this predisposition throughout the course of the trial. It was suggested that opening statements serve to create thematic frameworks which the jurors use to assist them in their processing of trial information. Implications for legal practice were also discussed.