Background: Osseous metaplasia can be found in some organs and tissues in course of calcium-phosphate balance disturbances. Individual cases of osseous metaplasia were reported in the parotitis sarcoma, hypophysis adenoma and carcinoma of mammary gland. In the literature there is no description of osseous metaplasia in colon.Case Report: The case of 16 years old girl with diagnosis of ulcerative colitis (UC) is presented. The features of osseous metaplasia in the inflamatorious polyp were found in histological examination in this case. Subsequently to focal osseous metaplasia in colon the determinations of calcium, phosphate and parathormone in blood were performed but no variations from standards were found. In literature the authors did not find any description of osseous metaplasia case in colon of patients with ulcerative colitis.Conclusions: Osseus metaplasia in colon in ulcerative colitis is a rare pathology that probably has no connection with this disease.

Keywords: osseous metaplasia, ulcerative colitis, children