A method for producing bags containing fiber material, comprises the steps of forming at least one continuous layer of fiber material; separating in succession portions of fiber material from the continuous layer and moving them along a predetermined path; feeding each portion of fiber material to respective containment and compaction elements of a first transfer conveyor; feeding an ordered succession of bags containing respective portions of fiber material to respective supporting elements of a second transfer conveyor; transferring the portions of fiber material into respective housings of a third transfer conveyor; transferring the portions from the third transfer conveyor inside respective containment bags carried by a second transfer conveyor; transferring the containment bags from the second transfer conveyor to a fourth transfer conveyor; and moving in succession the bags housing respective portions of fiber material to a folding unit at which the bags are closed.