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According to the classical definition for in-plane modes of crack deformation, the constant stress term T exists only in the presence of mode I. However, recent studies show that this term can exist in mode II conditions as well; and significantly affect the elastic stress field around the crack tip. These effects can be visualized using the experimental method of photoelasticity. Based on the analytical studies, presence of the T-stress in mode II cracks transforms the isochromatic fringe patterns from symmetric closed loops to asymmetric and discontinuous shapes. In this paper, presence of the T-stress in mode II cracks and its effects on the fringe patterns is investigated experimentally. The test specimens are Brazilian disks containing very sharp central cracks. After crack generation, all residual stresses are removed by performing a thermal process on the specimens. Then, compressive load is applied in specific angles to induce mode II deformation in the crack tips. Experimental results indicate that this specimen contains negative values of T-stress in pure mode II condition. The observed isochromatic fringes show very good agreement with theoretical predictions.