Provided are a method and an arrangement for feeding process gases from a suspension smelting furnace into a waste heat boiler. The arrangement comprises a feeding throat for feeding process gas. The feeding throat is connected to an uptake inner space at an exit. The feeding throat is connected to the waste heat boiler at an entrance. The feeding throat having a feeding channel comprising a channel inner roof. At least one of an uptake inner roof of the uptake of the suspension smelting furnace and the channel inner roof of the feeding channel of the feeding throat is provided with an angled and/or curved section that slopes at least partly downwardly in an angled and/or curved manner in the direction towards the entrance.