A continuous process for the manufacture of carboxylic peracids by reacting the corresponding carboxylic acid with hydrogen peroxide in the presence of a catalyst and in the presence of an inert organic liquid which is a solvent for the peracid and is capable of forming a heterogeneous azeotrope with water, removing the water present in the reaction mixture by distillation of the water/organic liquid azeotrope, and keeping sufficient water in the reaction mixture to allow the formation of an aqueous phase which is separate from an organic phase containing the organic liquid.