The mower blade with replaceable inserts includes a blade bar having diametrically opposite reliefs therein for replaceable cutting inserts. Headed pins extend from each relief, and each insert has corresponding slots. The slots have larger diameter outer ends to clear the larger diameter heads of the pins, the inner portions of the slots being stepped to fit closely about the narrower shanks of the pins. The inserts drop into position over the corresponding pins, and slide outwardly to be retained by the heads of the pins. The outer (lower) surfaces of the heads of the pins are coplanar with the outer (lower) surfaces of the inserts when installed. The cutting edge portions of the inserts extend over and are in direct contact with the corresponding leading edge portions of the blade bar, thus protecting the bar and transferring impact forces directly to the bar rather than through the pins.