The present invention relates in one aspect to an infusion fluid warmer which comprises a casing shell having an upper wall structure and a lower, opposing, wall structure. The casing shell encloses a fluid channel or passage extending through the casing shell in-between the upper and lower wall structures and fluid inlet and outlet ports coupled to opposite ends of the fluid channel or passage to allow a flow of infusion fluid through the casing shell. A housing shell is formed in a thermally conducting and electrically insulating material and a heating element is bonded to the housing shell and thermally coupled thereto. The fluid channel or passage extends through the housing shell or extends around the housing shell such that heat energy is transferred to the infusion fluid by direct physical contact with housing shell material.