Geometries and 29Si NMR chemical shifts are calculated for silanes SinH2n+2, n=1,…,5, methylsilanes SiHnMe4−n, methoxysilanes SiHn(OMe)4−n, and methylmethoxysilanes SiMen(OMe)4−n, n=0,…,4. Geometries and 29Si NMR chemical shifts are in satisfying agreement with experiment within LCGTO-DFT at the DZVP/LDA level for geometries and IGLO-III/GGA (GGA=PW91,PBE) level for shielding constants, which is an improvement to B88PW86, P86PW86 and B3LYP results. If an auxiliary basis is applied to express the Coulomb potential, g-functions have to be included to reproduce SiOSi angles and 29Si NMR chemical shifts correctly.