Formulae for the action of the Steenrod algebra on the mod 2 cohomology of a finite [italic]H-space are calculated. These formulae imply that the first nonvanishing homotopy group for a finite [italic]H-space occurs in degrees 1, 3, 7, or 15. The Steenrod algebra structure also restricts the coalgebra structure of the cohomology and Hurewicz map.