The influence of both TiOSO4 concentrations in the starting solution and a way of conducting hydrolysis on the degree of titanyl sulphate conversion to hydrated titanium dioxide were studied. Titanyl sulphate solution, an intermediate product in the commercial preparation of titanium dioxide pigments by sulphate method, was used. The continuous method of conducting hydrolysis was applied using one or two reactors connected in series. It was found that the degree of hydrolysis markedly depends on the studied parameters. It was also found that TiOSO4 hydrolysis using the continuous method should be conducted: i) at a possibly low concentration of free sulfuric acid in the solution and; ii) in two or more rectors connected in series.