Steam reforming or steam methane reforming (SMR) is a method for producing syngas (hydrogen and carbon monoxide) by reaction of hydrocarbons with water. Commonly natural gas is the feedstock. Steam reforming of natural gas produces most of the world's hydrogen. Hydrogen is used in the industrial synthesis of ammonia and other chemicals.

Steam Methane Reforming (SMR) is the cheapest way to make hydrogen commercially. Nearly 50% of the world's hydrogen production is done this way.

There are two stages to the reforming process.

In the first stage, methane reacts with water to produce carbon monoxide and hydrogen,

CH4 + H2O → CO + 3 H2

The second stage is the reaction of carbon monoxide with water

CO + H2O → CO2 + H2

Note: The main component of natural gas is methane.