Abstract: Objective To investigate the relationship between serum 25(OH) vitamin D and liver fat content in nonalcoholic fatty liver disease (NAFLD). Methods A total of 120 patients with NAFLD admitted in our hospital between June and August, 2017 were enrolled and divided into 4 groups with different serum 25 (OH) vitamin D levels: >75 nmol/L (group A, n=25), 50-75 nmol/L (group B, n=35), 25-50 nmol/L (group C, n=32), and <25 nmol/L (group D, n=28). For all the patients, serum 25 (OH) vitamin D level was measured by ELISA, and liver fat content was determined using in-phase opposed-phase T1WI sequences. The measurement data were compared among the 4 groups to assess the association between serum 25(OH) vitamin D level and liver fat content. Results The liver fat content appeared to be higher in group B (28.66±6.45%) and group C (38.74±11.47%) than in group A (22.79 ± 6.10%), but the difference was not statistically significant (P>0.05); the liver fat content in group D (54.79 ± 5.28%) was significantly higher than that in the other 3 groups (P>0.05). Liver fat content increased significantly as serum 25(OH) vitamin D level decreased, showing an inverse correlation between them in these patients (P<0.05, r=-0.125). Conclusion In patients with NAFLD, a decreased serum 25(OH) vitamin D level is associated with an increased liver fat content, suggesting the value of serum 25(OH) vitamin D as a predictor of NAFLD.