A novel procedure for ambient-pressure synthesis of pentacarbonyltechnetium halides [⁹⁹TcX(CO)₅] (X = Cl, Br) was developed. The procedure is based on treatment of K₂[⁹⁹TcX₆] with a mixture of HCOOH and H₂SO₄ on heating. With X = I, a mixture of [⁹⁹TcI(CO)₅] and [⁹⁹TcI(CO)₄]₂ was obtained. The products were characterized by elemental analysis and by ⁹⁹Tc NMR and IR spectroscopy.