Nanosized titania particles are prepared from titanium isopropoxide dissolved in alcohol and water under acidic conditions. The effects of the key parameters, including (alkoxide/water) ratio, HCl concentration, feed rate, and temperature, on the mean particle size and the standard deviation of size distribution of the final products are investigated through an experimental design technique. This technique can also be used to find the condition for obtaining transparent sols with mean particle size smaller than 50 run and standard deviation smaller than 5 run. We show that the main factors influencing the mean particle size and the standard deviation are (water/alkoxide) ratio, HCl concentration, and the interaction between these two factors. The present approach is applicable to finding the optimum conditions for preparation of titania with desired mean particle size and standard deviation.