Optimum conditions for the determination of silicon by flame emission spectrometry were ascertained. The maximum signal emanates from a region immediately above the tip of the inner cone of a fuel-rich oxygen-acetylene flame. The organosilicon compound is aspirated as a solution in ethanol and the emission intensity at 2516.1 Å is measured. Quantitative determinations were made using a working curve and by the method of standard addition. Detection limit is 3.5 μg/ml.