Mathematical models for the effects of the calcination process conditions on the mechanical properties of a PCoMo/Al2O3 hydrotreating catalyst are developed using a response surface methodology. A central composite design is performed to study collectively the effects of calcination temperature, calcination time and heating rate on the mean strength and Weibull's modulus. A model is obtained for each response with multiple regression analysis and then is refined. Analysis of variance reveals that the models developed are adequate. The validity of the models is also verified by experimental data. Statistics reveals that there is a great potential for increasing the mechanical reliability in the calcination process. Analysis of response surface show that the mean strength and Weibull's modulus increase with the increase of calcination temperature. The middle level of heating rate results in smaller mean strength and higher Weibull's modulus. The mean strength increases as calcination time increases. However, calcination time has no significant effect on Weibull's modulus in the experimental domain examined.