Organofunctional silica aerogels were prepared by base catalyzed hydrolysis and condensation of Si(OR')4 / RSi(OMe)3 mixtures, followed by supercritical drying. In the trialkoxysilanes, R is of the type (CH2)nA, the group A being an organic function. Amino, ethylenediamino, mercapto, cyano, vinyl, and methacrylate groups were thus incorporated in the aerogels. The sol-gel reaction of a 4:1 mixture of Si(OMe)4 and (vinyl)Si(OMe)3 was exemplarily monitored by Raman spectroscopy. The Raman spectra show that under basic conditions hydrolysis and condensation of Si(OMe)4 is much faster than that of (vinyl)Si(OMe)3. For the other RSi(OMe)3 precursors the reaction rates strongly depend on the electronic properties and the polarity of the functional organic group. Addition of the aminopropyl and cyanoethyl substituted precursors to Si(OR)4 results in shorter gel times relative to pure Si(OR')4, while the mercaptopropyl, methacryloxypropyl and vinyl substituted precursors retard gelation. Depending on the ratio and the kind of the precursors, 70 - 100 % of the functional organic groups were incorporated into the aerogel network. The hydrophobicity of the aerogels depends on the kind and amount of RSiO1.5 units.