Section 1 of the Sherman Act provides criminal sanctions for any person "who shall make any contract or engage in any combination or conspiracy" in restraint of interstate commerce. The act applies to both criminal and civil offenses, but it does not distinguish between them. The complainant must establish three elements to prove a violation of section 1 of the act: 1) that two or more entities formed a combination or conspiracy, 2) that the combination or conspiracy intended to produce an unreasonable restraint of trade or commerce, and 3) that the restrained trade or commerce is interstate in nature. In addition, in a criminal antitrust prosecution under section 1 of the act, the government must demonstrate that the defendant entities intended to restrain commerce and acted "with knowledge of the probable consequences" of their actions. This article discusses each of these elements in detail. Defenses to charges under the act pertain to meeting competition, limitation of actions, single entity, double jeopardy, "unsettled law," respondeat superior, withdrawal from conspiracy, regulated industry, and State-action immunity. Sanctions are discussed as they apply under approved new Sentencing Guidelines for Organizational Defendants, effective since November 1, 1991. 127 footnotes