Introduction <p>Since, as the global population ages and also, non-communicable diseases including type 2 diabetes is one of the most common challenges for public healthcare system worldwide present study aimed to the <i>relationship</i> of <i>vitamin D deficiency</i> with prediabetes and diabetes in older adults.</p> Methods <p>In this cross-sectional study 1324 older aged 60 years and older participated. A questionnaire containing demographic information, physical activity and smoking habits was completed by trained interviewers for all participants. Then, weight, height and waist circumference, Body Mass Index (BMI) also, systolic and diastolic blood pressures (mmHg) of all subjects were measured and calculated. Fasting blood sugar (FBS) after overnight fasting and serum 25OHD levels were measured. Analyses were conducted using Stata 17 software.</p> Results <p>The mean age of participants was 69.76 ± 7.56 years, and 52.0% were female. The mean serum 25(OH) D level was 31.14 ± 15.99 ng/mL, and 25.45% of participants were classified as vitamin D deficient. Diabetes and prediabetes were present in 29.08% and 22.96% of participants, respectively. In the fully adjusted ordinal logistic regression model, higher serum vitamin D levels were significantly associated with lower odds of having a worse diabetes status (adjusted OR = 0.90; 95% CI: 0.84–0.97; <i>p</i> = 0.006).</p> Conclusion <p>In conclusion, 25OHD deficiency was related with diabetes mellitus status in older adults after full control of multiple potential confounders. These findings support policy and awareness program related the importance of improving vitamin D for prevention of prediabetes and diabetes mellitus in older adult population.</p> Clinical trial number <p>Not applicable.</p> Graphical abstract <p></p>