The prevalance of osteoporosis or osteopenia in Turkish population with ulcerative colitis (UC) at the diagnosis time has not been evaluated so far. Therefore we aimed to determine the prevelance and risk factors of decreased bone mineral density (BMD) in UC patients at the diagnosis time in Turkey. We retrospectively evaluated dexa results, demographic and clinical characteristics, and some biochemical markers of bone turnover of the UC patients at the diagnosis time between June 2005 and February 2010 from the gastroenterology clinic records of the university hospital. The study population consisted of firstly diagnosed 63 UC patients (male: female = 27: 36; mean age 41.8 years). 38.1% at lumbar spine and 44.4% at femoral neck of the Turkish UC patients patients had low BMD at the diagnosis time. The occurrence of osteoporosis among Turkish UC patients at the diagnosis time were 8% at lumbar spine and 11% at femoral neck. 30.1% at lumbar spine and 33.3% at femoral neck of the patients had osteopenia at the diagnosis time. Pearson's coefficient of correlation showed significant correlations between low BMD and pancolitis (p<0.01), age, menopause, and symptom duration before the diagnosis (p<0.05). In conclusion, the prevelance of low bone density at the diagnosis time in Turkish UC patients is in accordance with Western and Eastern societies. Pancolitis, age, duration of symptoms, and menopause are predictive factors for low bone density in these patients.