Thermostatting device for containers of bio-medical fluids for parenteral administration, particularly bags for medical fluids, blood or the like, comprising: at least a container having at least one compartment for housing at least one flexible bag containing a bio-medical fluid, said container comprising at least a half-shell, and one door associated mobile with said half-shell for closing/opening said compartment; at least one portion of heat conductive surface suitable for being placed in contact with said bag when this is arranged inside said compartment; and heating means for heating said heat conductive surface to bring and/or keep to a preset temperature the fluid inside said bag; and retention means (9, 11, 12) for retaining said bag inside said compartment which are suitable for keeping said bag in contact with said heat conductive surface during the emptying of the bag itself; wherein the retention means (9, 11, 12) comprise at least a plate, associated with said container, arranged inside said compartment, and having at least a seat designed to accommodate said bag; the thermostatting device being characterized by that it comprises gripping means associated with said container and suitable for allowing it to a vertical upright, and by the fact that said half-shell comprises at least a bottom through hole for inserting an extremity of said bag having the mouth for fluid dispensing; and also by the fact that the seat comprises said heat conductive surface and defines a substantially sloped surface on which a face of the bag can be positioned, resting, so that the bag can be kept in contact with the heated surface of the seat during emptying by means of force of gravity only, while the retention means comprise a securing element associated with the door such that once the door is closed, the securing element is placed in contact with a face of the bag substantially opposite the seat, the securing element being capable of moving towards the bag by means of action of elastic means, and being capable of moving away from bag against elastic means. at least a container having at least one compartment for housing at least one flexible bag containing a bio-medical fluid, said container comprising at least a half-shell, and one door associated mobile with said half-shell for closing/opening said compartment; at least one portion of heat conductive surface suitable for being placed in contact with said bag when this is arranged inside said compartment; and heating means for heating said heat conductive surface to bring and/or keep to a preset temperature the fluid inside said bag; and retention means (9, 11, 12) for retaining said bag inside said compartment which are suitable for keeping said bag in contact with said heat conductive surface during the emptying of the bag itself; wherein the retention means (9, 11, 12) comprise at least a plate, associated with said container, arranged inside said compartment, and having at least a seat designed to accommodate said bag; the thermostatting device being characterized by that it comprises gripping means associated with said container and suitable for allowing it to a vertical upright, and by the fact that said half-shell comprises at least a bottom through hole for inserting an extremity of said bag having the mouth for fluid dispensing; and also by the fact that the seat comprises said heat conductive surface and defines a substantially sloped surface on which a face of the bag can be positioned, resting, so that the bag can be kept in contact with the heated surface of the seat during emptying by means of force of gravity only, while the retention means comprise a securing element associated with the door such that once the door is closed, the securing element is placed in contact with a face of the bag substantially opposite the seat, the securing element being capable of moving towards the bag by means of action of elastic means, and being capable of moving away from bag against elastic means.