The decomposition of alkoxymethylsilanes (C2H5O)4-xSi(CH3)x (x = 3, 2, 1, 0) on a hot Mo wire was investigated within the temperature range of 1300-1600 K and at pressures of 12-90 Pa. Within the temperature range 1400-1600 K a rate law of first order was determined. The activation energy of the decomposition Of (C2H5O)4Si was estimated to be 74.5 kJ mol-1. The rate constants k(x) of the x-methyl-(4 - x) ethoxy silane decomposition decreases with increasing x as k0:k1:k2:k3 = 9:9:3:1. From these results and the formed products as ethanol and ethene, a surface-activated decomposition mechanism is proposed assuming a two-center reaction of the alkoxy groups with the formed SiO2 surface on the wire. By esr spectroscopic investigations of condensed radicals the formation of radicals as C2H5, =Si-O-C2H4. and ROO. was confirmed.