AIM: To investigate the correlation between vitamin D levels and urinary incontinence in women with type 2 diabetes mellitus (T2DM). METHODS: A total 366 female T2DM patients who were hospitalized in Department of Endocrinology, First Hospital of Lanzhou University from May 2022 to July 2023 were selected and were classified as vitamin D deficiency (<20 ng/mL), insufficiency (20-30 ng/mL), and sufficiency (>30 ng/mL) according to serum 25-hydroxyvitamin D ［25(OH)D］ concentration. The prevalence of urinary incontinence and severity was compared among three groups. Adjusted logistic regression was used to analyze the correlation between vitamin D levels and urinary incontinence and its subtypes. RESULTS: Of the 366 patients, 174 (47.5%) T2DM with urinary incontinence. 25(OH)D level was significantly lower in group with urinary incontinence than without (11.9 ng/mL vs. 17.8 ng/mL, P<0.01). The prevalence of urinary incontinence and moderate and severe urinary incontinence was significantly higher in group with vitamin D deficiency than groups with insufficiency and sufficiency (P<0.05). Adjusted logistic regression analysis showed that vitamin D deficiency was associated with an increased risk of any incontinence and urgency incontinence compared to vitamin D sufficiency (P<0.05), vitamin D insufficiency was not associated with urinary incontinence. Age, BMI, parity and low 25(OH)D levels were independent risk factors for combined urinary incontinence in women with T2DM. CONCLUSION: Vitamin D deficiency is significantly associated with the risk of urinary incontinence in women with T2DM, and appropriate vitamin D supplementation may have some benefits for urinary incontinence.