Abstract: The invention is directed to an improved system for mounting a drop sensor onto a drip chamber having laterally projecting wing-like or flange-like extensions. A pair of mounting members, one fixed, one laterally movable, are provided on the drop sensor housing. The mounting members have inclined guiding surfaces which cradle both ends of the lateral extensions on the drip chamber during the initial stages of mounting the drop sensor to the drip chamber and guide drop sensor movement with respect to the drip chamber to its final mounted position thereon. The mounting system is particularly adapted to dedicated IV set and drop sensor combinations.