An adjustment assembly for snare wires includes an adjustment unit and a pressing unit respectively located on two opposite positions of the shell of a snare drum. The adjustment unit has a body with a slide slot. A shifting member is slidably connected to the body and driven by a driving member connected to the body. The shifting member has a wire carrier which is adjusted by rotating an adjusting bolt. The pressing unit includes another wire carrier which is controlled by another adjusting bolt. By adjustment of the two adjustment bolts, the tension of the snare wires can be adjusted.