National Small Business Regulatory Assistance Act of 2003 - Directs the Administrator of the Small Business Administration (SBA) to establish a pilot program to provide regulatory compliance assistance to small businesses through participating Small Business Development Centers (Centers). Requires the Administrator to enter into arrangements with participating Centers to provide: (1) access to regulatory information and resources; (2) training and education activities; (3) confidential counseling to owners and operators of small businesses regarding compliance with Federal regulations; (4) technical assistance; and (5) partnerships with Federal compliance programs.

Requires the Administrator, giving substantial weight to the recommendations of the majority of the Centers, to select the Center programs of two States from each of ten groups of States for participation in the pilot program. Provides grant limits. Terminates the pilot program four years after disbursement of the first grant.

Provides privacy requirements applicable to Centers, a consortium of Centers, or any Center contractor or agent with respect to regulatory compliance assistance provided to small businesses.