Ammonia is produced from a synthesis gas containing nitrogen and hydrogen on a granular catalyst in at least one reactor at pressures in the range from 50 to 300 bar and temperatures in the range from 100 to 600.degree. C. A product mixture containing NH.sub.3 vapor is withdrawn from the reactor, is cooled, and ammonia is condensed and separated. There is obtained a recycle gas to which fresh synthesis gas is admixed, the recycle gas being recirculated to the reactor as synthesis gas. Unreacted synthesis gas is passed through a first catalyst bed free of cooling tubes and subsequently as partly reacted synthesis gas with an NH.sub.3 content of 5 to 20 vol-% as heating fluid through a heat exchanger. Partly reacted synthesis gas is passed through at least one further catalyst bed, through which extend cooling tubes. Unreacted synthesis gas is passed as cooling gas through the cooling tubes of the further catalyst bed, and cooling gas heated to 300 to 500.degree. C. is introduced into the first catalyst bed. Unreacted synthesis gas flows through the cooling tubes and the further catalyst bed in a cocurrent flow.