Experimental evidences show that the effect of matric suction on stress and hence on shear and tensile strength of soil can be considerable, but limited in dry soils by the onset of cracking (Favaretti, 1995). In the present paper, several laboratory results, obtained by means of the Brazilian test are shown. Results of tensile strength of a soil were obtained using the diametral compression test, or Brazilian test, following the technique proposed by Krishnayya & Eisenstein (1974), Maciel (1991); Das et al. (1995) and Favaretti (1995). These tests consist of transversally compressing cylinders of soil throughout its generating line to cause them to fail by tensile throughout the diameter of the transversal section. Various tests were carried out on different levels of humidity and the results were correlated with the physical indexes. The samples were prepared in the laboratory from slurry condition, saturated with two different fluids. Their moisture retention curves were also determined. It was verified a high level of osmotic suction, which allowed to analyze separately the influence of the matric and total suction in the tensile strength behavior. It was observed that the total suction seems to control the soil tensile strength rather than the matric suction.