Drying induced stresses may cause irreversible deformations (warping) or even fracture of dried products. This paper concerns the fracture phenomenon in capillary porous materials by drying. A short presentation of the mechanistic model of drying elaborated earlier by author is given. This model enables calculation of the drying induced stresses and their distribution in dried elements, and thus the identification of the place of maximal stress appearance. The strength of dried material, being a function of the moisture content, is determined based on the known Condon-Morse model of particle interactions. Comparison of the actual maximal stress with the admissible stress for the given material allows formulation of the fracture criterion.