Spherical polysilsesquioxane particles are prepared by reacting trialkoxysilanes of formula, (I) RSi(OR1)3  (I), where R represents a C1-16 hydrocarbon radical whose carbon chain may be interrupted by nonadjacent —O— groups, R1 represents a C1-4 alkyl radical, with acidified water having a pH≤6 with stirring to produce a hydrolysate, in a second step mixing the hydrolysate with a solution of NaOH and/or KOH, and in a third step storing the mixture is stored for at least 8 h before isolating polysilsesquioxane particles thus formed.