Spherical TiO//2 powders were formed by the controlled hydrolysis of ethanol solutions of titanium tetraethoxide in a continuous stirred tank crystallizer. Particle size distributions were evaluated and the results used to determine both nucleation and growth rate as a function of reactant concentration. At high concentration, nucleation and growth were less important than agglomeration. A theoretical model incorporating agglomeration is presented. It predicts the conditions when agglomeration is observed in the continuous stirred tank.