Patent Litigation Integrity Act of 2013 - Requires courts to award a prevailing party reasonable fees and other expenses, including attorney fees, incurred in connection with a civil action in which any party asserts a claim for relief arising under any Act of Congress relating to patents, unless the court finds that the position and conduct of the nonprevailing party were substantially justified or that special circumstances make an award unjust. (Currently, in exceptional cases, the court is permitted but not required to award reasonable attorney fees.)

Authorizes courts, in response to a motion, to order the party alleging infringement to post a bond sufficient to ensure payment of such fees and expenses of the accused infringer.

Directs a court, in determining whether such a bond would be unreasonable or unnecessary, to consider whether:

• the bond will burden the ability of the party alleging infringement to pursue activities unrelated to the assertion, acquisition, litigation, or licensing of any patent;
• the party alleging infringement is an institution of higher education or a non-profit technology transfer organization;
• a licensee, who has an exclusive right under a patent held by such an institution of higher education or non-profit organization, conducts further research or development to make the subject matter more licensable;
• the party alleging infringement: (1) is a named inventor of or an original assignee to an asserted patent, (2) makes or sells a product related to the subject matter described in an asserted patent, or (3) can demonstrate that it has and will have the ability to pay the accused infringer's fees and other expenses if so ordered; and
• any party will agree to pay the accused infringer's shifted fees and other expenses, provided that the party can demonstrate an ability to pay.