Introduction: Vitamin D deficiency(VDD) is a common condition in all ages worldwide, especially in winter, and causes several adverse cardiovascular outcomes. Although there is conflicting information about the causes of adverse cardiac events in VDD, the accepted leading cause is a pathogenic relationship with hyperparathyroidism. Aim: We aim to demonstrate hyperparathyroidism’s effects, if present, on endothelial and diastolic functions using echocardiography, carotid, and brachial tissue Doppler imaging (tDi) in premenopausal women with VDD independent from confounding risk factors. Methods: Our study is a cross-sectional, observational study investigating premenopausal women aged 18-50 who applied to internal medicine department. The patients are divided into two groups according to parathyroid hormone(PTH) levels (Normal PTH 41 patients, abnormal PTH 27 patients). Study groups are analyzed for basal characteristics, standard echocardiographic evaluation, carotid, and brachial artery tDi features. Results: There were no significant differences in age, height, weight, body mass index(BMI), and blood pressures between the groups (all p values>0.05). The rate of severe VDD was 76%. In terms of diastolic parameters, prolongation of A wave durations and decreased E/A ratio were observed in the secondary hyperparathyroidism (p values 0.042 and 0.031, respectively). Also, carotid IMT is significantly higher in secondary hyperparathyroidism(p=0.034). Conclusion: Our study showed that high PTH levels have adverse effects on diastolic(A wave, E/A ratio) and endothelial functions(carotid IMT) in premenopausal women diagnosed with VDD, even in the absence of other confounding risk factors. We can state that our study’s findings will contribute to the literature and are predictive for future studies.