A method and an arrangement for sterilizing, in particular for sterilizing an adsorber, which has an adsorber housing that is to be filled with an adsorbent, are such that, instead of the adsorbent-filled adsorber housing being sterilized, the adsorbent is sterilized in a separate container, which is dimensioned such that the adsorbent spreads out in a thin layer in the container. Together with the adsorber housing, the container for sterilizing the adsorbent forms a closed system, such that the adsorbent can be transferred into the adsorber housing without the need for an aseptic environment. The container for receiving the adsorbent is preferably a bag, in which the adsorbent spreads out in a thin layer when the bag is lying flat on a plane surface. Since the adsorbent in the bag spreads out in a thin layer, the sterilization requires only a relatively small dose of radiation, which cannot damage the adsorbent. The bag is irradiated with high-energy radiation, in particular ionizing radiation. The adsorbent is then transferred from the bag into the adsorber housing. During the transfer of the adsorbent into the adsorber housing, the air and/or excess liquid present in the adsorber housing is removed from the adsorber housing preferably into one or more empty bags.