28 CFR 21.6: Proceedings in forma pauperis.
Title 28 U.S.C. 1915 provides for the commencement, prosecution or defense of any suit, action, or proceeding without prepayment of fees and costs. Witnesses shall attend as in other cases.
There are currently no provisions for payment of witnesses called by the indigent. If the indigent party prevails, witness fees and expenses may be taxed as costs in accordance with 28 U.S.C. 1920.
Rule 17(b), Federal Rules of Criminal Procedure, requires that fact witnesses subpoenaed on behalf of an indigent defendant be paid in the same manner as witnesses called on behalf of the Government. The attendance must be certified by the presiding officer of the court. The expenses of Federal Government employees are treated in the same manner as they are treated when the employee is called by a Government attorney.