The invention relates to a method for processing concentrates, particularly concentrates produced from copper sulfide-based ores. According to the method, the concentrate (4) to be processed, obtained from ore concentration, is divided into two parts, to a concentrate (7) mainly containing poorly soluble components, and to a concentrate (8) mainly containing well soluble components. The concentrate (8) containing well soluble components is conducted to a leaching step (9), and the solution (13) obtained from said leaching step is conducted to at least one conversion step (11, 16), and to the conversion step (11) that is located first in the flowing direction, there is fed the concentrate (7) containing poorly soluble components. In the conversion step (11) that is located first in the flowing direction, at least the copper contained in the solution is converted into sulfidic form by means of the sulfide-form iron of the concentrate (7) containing poorly soluble components, and at least part of the solution (12) obtained from the conversion step (11, 16) is returned to the leaching step (9).