The invention relates to a method and device for the injection of oxygen in a reformer reactor, for example, for oxydehydrogenation, with an essentially radial throughflow of the gas mixture through a catalytic packing, whereby the incorporation and mixing of the oxygen before entry into the catalyst is significantly improved, in particular for oxydehydrogenation methods. The above is achieved, whereby the oxygen is introduced in pure form, as air, or mixed with inert gas, or with steam, into an annular distribution system (5) and injected out of a number of outlet openings (6) in the annular distribution system, at an angle to the perpendicular, onto the catalyst surface (3).