Pinacolborane (1.05 equiv) hydroborates both terminal and internal alkynes, in the presence of 5 mol % zirconocene chloride hydride (HZrCp(2)Cl) at 25 degrees C, in excellent yields and with excellent regio- and stereoselectivity. Without HZrCp(2)Cl and under otherwise identical conditions, hydroboration proceeds to an extent of only 2-20%.