A process for the production of a valve metal oxide powder, in particular an Nb.sub.2O.sub.5 or Ta.sub.2O.sub.5 powder by continuous reaction of a fluoride-containing valve metal compound with a base in the presence of water and calcination of the resultant product, wherein the reaction is performed in just one reaction vessel and at a temperature of at least 45.degree. C. Valve metal oxide powders obtainable in said manner which exhibit a spherical morphology, a D.sub.50 value of 10 to 80 .mu.m and an elevated BET surface area.