A quasiclassical trajectory surface hopping (TSH) method is employed to study the O(P-3, D-1) + SiH4 reaction with special emphasis on the contribution of nonadiabatic path in the formation of various products. Tully's fewest switches algorithm is used to compute nonadiabatic transitions. Our calculation showed that while the H formation is the most important channel for the O(P-3) reaction with SiH4, the OH formation is the dominating channel for the O(D-1) reaction, at an initial collision energy of 8 kcal/mol. Comparison with a recent crossed molecular beam experiment shows qualitative agreement so as to primary product branching ratios, except for the formation of H2O from the O(D-1) reaction that was not detected experimentally. In addition our calculation revealed a major contribution (similar to 50%) of the H3SiO + H channel from the O(P-3) + SiH4 reaction through an addition complex H4SiO intermediate which was also not explored, experimentally. (C) 2017 Elsevier B.V. All rights reserved.