A process for producing pig iron is described, which contains a reducing shaft furnace 1 and a melting gasifier 2. The sponge iron produced from iron ores in the reducing shaft furnace is supplied to the melting gasifier and converted there into a pig iron melt. The gas produced in the melting gasifier is supplied directly via a line 4 as reducing gas to the reducing shaft furnace. The blast furnace gas passing out of the reducing shaft furnace, after traversing a CO.sub.2 scrubber 6, is at least partly heated in a heat exchanger to 200.degree. to 500.degree. C. and passed to a partial combustion plant 13 where, accompanied by the addition of oxygen, the gas is heated to the necessary reducing temperature.