Purpose: We aimed to evaluate the comparative efficacy of metformin and pioglitazone coadministered with high dose VD on clinical, biochemical, hormonal and insulin sensitivity parameters in women with PCOS. Material and Methods: In this open label randomised study, a total of 136 women, aged 18-40 years, diagnosed with PCOS as per the AE PCOS 2009 criteria, were randomly assigned into four groups (n=34 per group). The four groups received Metformin-1gm/day alone, metformin-1gm/day+cholecalciferol4000IU/ d,pioglitazone-30mg/day alone and pioglitazone- 30mg/day+cholecalciferol-4000IU/d.The clinical, biochemical, hormonal and insulin sensitivity parameters were evaluated at 0, 3 months and 6 months after the intervention. Results: The mean age of subjects was 21.89±4.99 years with mean BMI of 22.19±3.24kg/m2. The mean serum 25OHD level at the baseline in the metformin+VD and pioglitazone+VD group was 13.28±8.44ng/ml and 11.17±7.46ng/ml and it improved to 63.33±19.76ng/ml and 57.69±14.43ng/ ml respectively after six months of intervention. The mean no. of cycles/year and Ferriman-Gallwey (FG) score improved in all four arms. Significant decrease in the total serum testosterone level was observed in the groups that received VD in addition to metformin and pioglitazone, the effect being more significant in the metformin+VD group (64.60±23.59ng/dl at 0 months to 41.24±12.83ng/dl after 6 months). Plasma glucose and insulin levels from a two-hour OGTT showed a significant improvement in subjects receiving VD in addition to pioglitazone. Conclusion: Metformin and pioglitazone are equally efficacious for treatment of women with PCOS. High dose oral cholecalciferol co-administration significantly improved the metabolic outcomes among these women.