One of the complications of ulcerative colitis with frequent relapses is mineral deficiency (potassium, calcium, magnesium and phosphorus). The objective of the present work is to examine the bone density and laboratory parameters of bone metabolism in 25 patients with a medium severe and severe form of ulcerative colitis. In patients with ulcerative colitis a significantly reduced bone density was found in the era of neck of the femur (p < 0.05), a a non-significantly reduction of the bone density in the era of the lumbar vertebrae and an elevated level of osteocalcin (p < 0.05). These findings indicate a higher prevalence of bone changes in patients with ulcerative colitis. Early detection of bone changes makes adequate prevention and treatment of bone complications possible.