Abstract: An iron-containing catalyst for ammonia synthesis, characterized in that it contains the promoters potassium, calcium and aluminum, wherein the proportion of potassium, calculated as K2O, is 0.08% to 0.6% by weight, the proportion of calcium, calculated as CaO, is 0.8% to 2.2% by weight and the proportion of aluminum, calculated as Al2O3, is 1.0% to 2.3% by weight, is described. The invention further relates to the production of the catalyst according to the invention and to a process for ammonia synthesis using the catalyst according to the invention.