The exact reason for the development of inguinal hernia has not been completely determined. However, it is known that the fascia transversalis (FT) is one of the structures preventing development of hernias. In the etiology of the inguinal hernia, disorders in collagen metabolism have been proposed, and the role of metalloproteinases in remodeling the collagen has recently been of great importance. We could not encounter any study where the role of metalloproteinase inhibitors was evaluated in inguinal hernia. We obtained samples of FT from patients with direct and indirect hernia and used an immunohistochemical method to determine tissue inhibitor of metalloproteinase-2 (TIMP-2) expression. In the study group, samples of FT were taken during the operation from 45 patients, of which 35 were indirect and 10 were direct inguinal hernias. In the control group, samples of FT from various abdominal incisions were also taken from 45 patients with no hernia and operated upon for another pathology. TIMP-2 scores of a direct inguinal hernia were significantly less than those of the control group. However, no difference has been found between the TIMP-2 scores of an indirect inguinal hernia and those of the control group. Decreased TIMP-2 scores in patients with a direct inguinal hernia, compared with both the indirect inguinal hernia group and the control group, explain the reason for the increase in matrix metalloproteinase-2 (MMP-2) that has been proposed in some studies. Therefore, it can be expressed that a decreased activity of TIMP-2 plays a role in inguinal hernia development.