Corn. catalysts of the steam reforming (products of the Fertilizers Research Institute, PL) were analyzed for mech. strength, activity, Ni dispersion, and Ni active surface after long-term operation (up to 8 years) under industrial conditions in 5 plants. The loss of the catalyst activity was high on the inlet to the catalyst bed. The deactivation resulted in an increase of the tubular reactor wall temp. by more than 20 degrees C as well as an increase of the outlet gas temp. by 8 degrees C after 8 years. An increase of the MeH content in the gas was also obsd. No remarkable deterioration of the mech. strength of the catalyst and no increase in the gas flow resistance were found.