The e.s.r. spectra of a variety of silyl radicals have been observed during the steady-state photolysis of di-t-butyl peroxide in the parent silane. In a number of cases, in addition to the proton hyperfine interactions, splittings from 29Si in natural abundance have been observed. Unlike the analogous alkyl radicals, silyl radicals are non-planar around the atom bearing the unpaired electron. In the series (Me)nSiH3–n the radicals probably become less planar as Me is replaced by H.