A mulch plate adjustment apparatus for use with lawn mowers. The adjustment apparatus is used to adjust the height of a mulch plate attached to the lawn mower and to secure the mulch plate at the desired height by the use of a handle and handle-locking ratchet mechanism. The adjustment apparatus is affixed to the discharge chute of a lawn mower. The apparatus includes a handle-operated mulch plate raising-and-lowering mechanism that allows the mulch plate to be adjusted to different heights to accommodate different sized lawn mowers and different mowing conditions. The operator of the mulch plate adjustment apparatus can select a desired height for the mulch plate and safely secure the mulch plate at the selected height by simple operation of a handle. Further, the mulch plate apparatus provides a mechanism for allowing the mulch plate to be raised in a storage position without the need to provide extension wires or cables.