Abstract: Process for the treatment of a lateritic nickel/cobalt ore consisting of a mixture (2) of limonite and saprolite, characterized in that: the mixture (2) in the presence of an iron-precipitating agent is made into a pulp (1), having a solids content of between 10 and 40% by weight; the pulp undergoes a leaching operation (4) with sulphuric acid (5), at a temperature between 70° C. and the boiling point and at atmospheric pressure; and a solid-liquid separation (8) is carried out so as to obtain an iron-containing solid residue (9) and a solution containing nickel and cobalt ions. Process for producing nickel and/or cobalt intermediate concentrates or commercial products using the above process.