Devices for the preparation of depleted blood products that provide for the depletion of oxygen, carbon dioxide, or oxygen and carbon dioxide are described. A depletion device (100) comprises an enclosure (103), one or more liquid chambers (101) and one or more depletion chambers (102). A gas permeable barrier (107) separates the liquid chamber(s) from the depletion chamber(s). The depletion chamber contains depletion media (106) such as a solid O