Silicon is a major constituent of grasses, therefore, research was initiated to evaluate the use of the paraffin technique for electron probe microanalysis of Si in grass leaf tissue. Mature healthy leaves of a tropical grass, Wilmington bahiagrass (Paspalum notatumFlügge), and a cool season grass, tall fescuegrass (Festuca arundinaceaSchred), were selected for study. Paradermal sections (10 μ) of paraffin impregnated leaf tissue were placed on sheet carbon that had been attached with Haupt's adhesive to 2.5 cm glass discs. The grass sections were fixed to the sheet carbon with Haupt's adhesive and the paraffin removed with xylene prior to microanalysis. Silicon was found to be highly concentrated in the epidermis of fescuegrass and bahiagrass. Short cells, many containing opal bodies, had the highest contents of Si of the epidermal cells. Large quantities of Si was also present in guard cells but long cells contained relatively small amounts.