The hydrogen production system for internal combustion engines includes an intake air scoop, a vacuum block having an air input port system for receiving air from the intake air scoop, a water reservoir connected to the vacuum block for providing water to be mixed with the air in the vacuum block, at least one primary generator assembly with an inlet port for receiving the air/water vapor mixture from the vacuum block and producing a mixture of hydrogen, produced oxygen, and fine hydrogen production vapor from a partially oxidized water fog, and a plurality of secondary hydrogen generator assemblies connected to the primary generator assembly for receiving this mixture. The engine vacuum draws this mixture into the intake manifold to provide an ideal fuel mixture for the engine.