The scope of this work consisted of producing pure zirconia powders, yttria stabilized zirconia powders and ceria stabilized zirconia powders from zirconium oxychloride and yttrium and cerium chlorides using urea as precipitating agent and polyacrylic acid as dispersing agent. A factorial analysis was designed to study the effects of some precipitation variables (precipitation temperature, precipitation time, urea concentration, yttria concentration, ceria concentration and polyacrylic acid concentration) on the thermal behavior of zirconia gels using differential scanning calorimeter (DSC). It was observed that the addition of yttrium and cerium in the solution raised the crystallization temperature of the gels, due to changes on the characteristics of the Zr-OH bonds caused by the substitution of zirconium by yttrium or cerium. For the ZrO2-Y2O3 system, the presence of polyacrylic acid increased the crystallization temperature. It was suggested that polyacrylic acid promoted the formation of a random polymeric structure of zirconia gels that required higher temperatures to crystallize.