Abstract: The invention relates to a process for preparing hydrogen by reforming hydrocarbons with steam, and for separation of carbon dioxide. The process includes one endothermic and one autothermal reforming step for production of a synthesis gas stream, wherein heat generated in the autothermal reforming step is utilized for heating in the endothermic reforming step. The process also includes a step of converting the synthesis gas stream obtained for enrichment with hydrogen, a step of separating the hydrogen thus prepared by pressure swing adsorption, and a step of separation of carbon dioxide from the residual gas obtained in the pressure swing adsorption. The reforming units for the endothermal and autothermal reforming steps are arranged parallel to one another or in series.