The calibrated medicine mixing assembly preferably includes a primary reservoir having a primary cavity adapted to receive the fluid. The primary reservoir preferably including calibrated fluid level indicia displayed on an outer surface. Such an assembly may further include a secondary reservoir preferably having a secondary cavity adapted to receive the powder agent. The secondary reservoir preferably including calibrated level indicia displayed on its outer surface. The secondary reservoir is further removably positioned into the primary reservoir such that a major surface area of the secondary reservoir is completely submerged inside the primary reservoir. A plurality of orifices may preferably be formed along a top region of the secondary reservoir, the orifices further situated inside the primary reservoir, thereby causing the secondary cavity to be in fluid communication with the primary cavity when the secondary reservoir is situated within the primary reservoir.