In this letter, we report a new and extremely rapid technique for surface modification, which we term laser activation modification of semiconductor surfaces or LAMSS. This method consists of wetting a semiconductor surface ( e. g., silicon or germanium) with a reactive compound and then firing a highly focused nanosecond pulse of laser light through the transparent liquid onto the surface. The high peak power of the pulse at the surface activates the surface so that it reacts with the liquid with which it is in contact. Evidence for functionalization of the spots is given by ToF-SIMS imaging and small-spot XPS.