Background: Non-alcoholic fatty liver disease (NAFLD) is a highly prevalent condition. Emerging evidence suggests that vitamin D (VD) may play a role in the pathogenesis of NAFLD. Objective:  Studying VD status in patients with NAFLD. Patients and Methods:Seventy five patients were divided into 5 groups: Group (1) Diabetic patients with NAFLD, Group (2): Dyslipidemic patients with NAFLD, Group (3): Non-diabetic, non-dyslipidemic patients with NAFLD, Group (4): Diabetic patients without NAFLD, and Group (5): Healthy subjects (age and sex matched).   All subjects were subjected to full history taking, clinical examination and laboratory investigations including assessment of serum VD, fasting insulin, lipid profile, blood glucose, AST and ALT, and assessment of IR by determination of HOMA-IR. This were in addition to abdominal ultrasonography and using Hamaguchi score to evaluate fatty liver state. Results: VD significantly decreased in all NAFLD patients (groups 1, 2 and 3), in addition to group 4 (diabetic patients without NAFLD), compared with group (5). This association was independent from age, sex, insulin resistance (IR), or liver functions. Also, VD significantly decreased in males of group 2 compared to females of same group. Moreover, there was significant negative correlation between VD and US score of NAFLD patients. Conclusion: VD was deficient in patients with NAFLD and diabetic patients without NAFLD. This association was independent from age, sex, diabetes, IR or liver functions. The greater the degree of NAFLD, the greater was the degree of VD deficiency. Also, there was an inverse correlation between VD and US score.