Objective To investigate the levels and clinical significance of serum 25-hydroxy vitamin D[25(OH) D] in patients with chronic liver disease.Methods A total of 153 hospitalized patients with chronic liver disease in the First Affiliated Hospital of Jilin University from June 2012 to September 2013 were enrolled in the study group.The levels of serum 25(OH) D were measured by liquid chromatography tandem mass spectrometry.The serum samples from 300 healthy volunteers who underwent physical examination in our hospital were used as controls.The study group was divided into three subgroups: non-cirrhosis,liver cirrhosis [Child-Pugh(CP) grades A,B,and C],and primary biliary cirrhosis.Comparison of continuous data between groups was made by t test and analysis of variance,and comparison of categorical data was made by chi-square test.Correlation between different variables was investigated by Pearson linear regression analysis.Results Of the 153 patients with chronic liver disease,the percentages of those who had vitamin D adequacy(≥30 ng / ml),insufficiency(20-30 ng / ml),deficiency(10-20 ng / ml),and severe deficiency(< 10 ng / ml) were 20.3%,22.9%,35.9%,and20.9%,respectively.The percentages of patients with vitamin D deficiency and severe deficiency were significantly higher in the cirrhosis subgroup than in the non-cirrhosis and primary biliary cirrhosis subgroups(41.7%,25.0% vs 27.5%,12.5% and 23.5%,17.6%,respectively; χ2= 6.261-18.474,P = 0.001-0.012).The serum 25(OH) D levels in patients with cirrhosis were significantly lower compared with those in patients without cirrhosis and in controls(18.58 ± 12.48 vs 23.78 ± 11.81 and 25.69 ± 12.39 ng / ml,P = 0.029 and0.001).CP class C cirrhotic patients had significantly lower serum levels of 25(OH) D compared with CP class A patients(P = 0.009).Conclusion Serum 25(OH) D deficiency is common in patients with chronic liver disease.25(OH) D levels in cirrhotic patients,especially in CP class C patients,are markedly lower than those in non-cirrhotic patients.