Legislative Oversight of Significant Regulations Act of 2003 - Revises provisions governing the congressional review of agency rulemaking. Imposes review requirements upon only rules described as "significant" in the authorizing Act. Prohibits a significant rule from taking effect before the enactment of a joint resolution comprising solely of the text of such rule.
Requires the report submitted by a Federal agency proposing a significant rule to include an explanation of the specific statutory interpretation under which a rule is proposed, including an explanation of whether the interpretation is expressly required by the text of the statute or, if not, an explanation that the interpretation is within the permissible range and an explanation of why the interpretation was selected. Provides that if Congress fails to enact a joint resolution approving a proposed significant rule, no court or agency may infer any intent of Congress from any action or inaction with regard to such rule or related statute.
Sets forth: (1) the congressional approval procedure for significant rules (current law sets forth disapproval procedure for rules); and (2) provisions with respect to revising or revoking an existing rule by joint resolution.