S.2519 - Federal Government - A bill to prohibit the awarding of a contract or grant in excess of the simplified acquisition threshold unless the prospective contractor or grantee certifies in writing to the agency awarding the contract or grant that the contractor or grantee has no seriously delinquent tax debts, and for other purposes.

Contracting and Tax Accountability Act of 2007 - Prohibits any person who has a seriously delinquent tax debt from obtaining a federal government contract or grant. Requires federal agency heads to require prospective contractors or grantees to: (1) certify that they do not have such a debt; and (2) authorize the Secretary of the Treasury to disclose information describing whether such contractors or grantees have such a debt.

Defines "seriously delinquent tax debt" and an outstanding tax debt for which a notice of lien has been filed in public records.