This work aims to determine the effect of heat treatment at 85 degrees C at three different durations (1 h, 2 h and 3 h) on scratch behavior and microhardness of polymethylmethacrylate (PMMA). Microhardness test results showed that microhardness values increase with increasing the heat treatment durations according to the neat PMMA samples. Scratch test results showed that heat treatment at 3 h results in the best scratch-resistance due to higher surface hardness as compared to other samples. Moreover, scratch deformation mechanisms of PMMA samples were determined by using a scanning electron microscope (SEM). Two important damage mechanisms were determined as "ironing" and "cracking" for heat treated PMMA samples. (C) 2014 Elsevier Ltd. All rights reserved.