Background: Nationwide studies assessing sociodemographic factors associated with poor vitamin D status and efficacy-safety of vitamin D supplementation in Indian clinical practice are limited. Methods: In this multicenter, prospective, non-interventional study, patients with vitamin D deficiency (25[OH]D <20 ng/mL)/insufficiency (25[OH]D 21-29 ng/mL) were enrolled at 9 sites across India and prescribed vitamin D supplements per routine practice. Primary endpoints were patient profiles associated with vitamin D deficiency/insufficiency and change in visual analog scale (VAS) scores for clinical signs/symptoms from baseline to weeks 4 and 8. Key secondary endpoints were prescription pattern of vitamin D supplements and incidence of adverse drug reactions (ADRs)/serious ADRs. Change in systolic/diastolic blood pressure (SBP/DBP [hypertensive patients]) and glycated hemoglobin (HbA1c [diabetic patients]) were assessed from baseline to weeks 8 and 12, respectively. Paired t test was used to assess statistical significance, except for patient profile association, where analysis of variance model was used. Results: Of 201 enrolled patients (mean [standard deviation] age: 43.4 [14.52] years), 61.7% were women. Most demographic and anthropometric factors, except for current sunscreen use (p=0.0297) and socioeconomic status (p=0.0222), were not significantly associated with vitamin D deficiency/insufficiency. Upper-lower class had significantly higher odds (p=0.033) for vitamin D deficiency versus insufficiency versus lower class. Most of the patients were prescribed 60000 IU/week orally. VAS scores for bone and lower back pain, bone loss, low bone mineral density, and muscle pain were significantly reduced at weeks 4 and 8 (p<0.001). SBP/DBP of hypertensive patients and HbA1c of diabetic patients were also significantly decreased (p<0.05). No ADRs/serious ADRs were observed. Conclusion: Sunscreen use and socioeconomic status were significantly associated with vitamin D deficiency/insufficiency. Vitamin D supplementation improved clinical symptoms, HbA1c levels (diabetic patients), and SBP/DBP (hypertensive patients), without any adverse safety outcomes. Nevertheless, studies with long-term follow-up and larger sample sizes are warranted.