A cylinder head for internal combustion engines, with a device for the pneumatically assisted direct injection of fuel into at least one cylinder provided with at least one spark plug and a valve aperture with its relative valve, fuel feed means being provided, the valve being connected to a chamber into which said feed means cause the fuel to flow. The chamber is connected to a feed duct directly associated with an air pipe and an oil pipe, a piston acting within the chamber in order, during its compression stroke, to inject the air-fuel mixture generated in the chamber into at least one cylinder via the valve aperture, the piston being operated mechanically by a positive transmission driven by the crankshaft.