Transforming growth factor-β1 (TGF-β1) plays a role in the pathogenesis of ulcerative colitis (UC) by activating its specific receptors (TβRI-TβRIII). We investigated the expression of genes encoding for TGF-β1 and TβRI-III using RT-QPCR in patients with active and inactive UC and non-IBD controls. The localization and level of TGF-β1 protein in intestinal tissue was estimated by immunohistochemistry, and serum TGF-β1 concentrations were determined using ELISA. We found a significant increase in TGF-β1 gene expression and increase in the expression of genes encoding receptor TβRI in patients with active UC when compared with controls. The expression of genes encoding TβRII was found to be higher in patients with both active and inactive UC when compared to controls. Specific staining for TGF-β1 in fibroblasts was significantly greater in both active and inactive UC as compared to controls. The serum concentration of TGF-β1 was significantly higher in patients with active UC when compared with controls as well as in UC patients with left side/total colonic extension when compared with those with disease limited to rectum/rectosigmoid area. However, no correlation between TGF-β1 serum concentrations and UC activity index was found. Increases in TGF-β1 gene expression and its protein level, associated with altered TGF-β1 receptor profile indicate a functional role for TGF-β1 in intestinal inflammatory/repair processes in UC. Increases in TGF-β1 serum concentrations correlate with extension of disease.