Abstract: An in-situ method and apparatus for monitoring wear of a dicing saw blade. The apparatus, which is mounted on a cooling block of the dicing saw, has a transmitter to emit a parallel beam of light onto a side surface of the dicing saw blade; a receiver for receiving the light that is un-obscured by the saw blade; and a processor coupled to the receiver for determining wear of the saw blade based on an output from the receiver. The apparatus may also display the wear rate of the saw blade, and/or an estimated time for replacement of the saw blade.