The Federal Sentencing guidelines provide that a defendant's sentence must be enhanced for obstruction of justice. The guidelines cite perjury as an example of the type of conduct for which this enhancement should apply. This article first describes the two preguidelines options available to courts to punish defendant perjury: using the contempt sanction to punish perjury that obstructs justice and considering defendant perjury as an indicator of the defendant's poor prospects for rehabilitation when sentencing for the conviction offense. The author then reviews the change in sentencing philosophy that accompanied Congress' adoption of the guidelines and the split of authority among the courts of appeals concerning the effect that the new philosophy should have when enhancing guidelines sentences for alleged perjury. The author argues that, in applying the guidelines, the circuit courts have relied on inapposite case law while ignoring the historical distinction between simple perjury and perjury that rises to the level of obstruction of justice. He further argues that by ignoring this historical distinction, the courts have eliminated the need for prosecutors to bring a perjury charge against defendants alleged to have testified falsely, thus impairing a defendant's right to a trial on the perjury charge. The author proposes a solution to harmonize the judge's need to control a defendant's behavior and the defendant's right to present a defense within the structure of the guidelines. 244 footnotes and an appended sentencing table