Background. To date, the fact and mechanisms of associative links between vitamin D deficiency and primary hyperparathyroidism (PGPT) have been established. In turn, the level of 25(OH)D is influenced by climatic conditions and the presence of obesity (Ob). These set the purpose of the study— to determine the supply of vitamin D in patients with endocrine disorders living in the climate in Ukraine, and to assess the impact of Ob on vitamin D levels and the development of hypercalcemia— signs of PGPT. Materials and methods. BMI, serum calcium (Ca) and vitamin D levels in 145 patients who were in the endocrinology clinic for various endocrine pathologies were studied. The frequency of vitamin insufficiency and vitamin D efficiency, hypercalcemia in groups with and without obesity was analyzed. Results. The proportion of obese in the general group was 33.8%, among men— 28.57%, among women— 35.04% (p < 0.05). The level of Ca in the blood was 2.39±0.02 mmol/l, high Ca level occurred in 16.55%, and Ob— іn 49 (33.49%) patients. Against the background of Ob, the level of Ca was 2.42±0.02, and in non-obese people— 2.38±0.02 (p>0.05). Average level of vitamin D in the blood in the general group was 22.95±0.73mg/ml and was probably lower in individuals with Ob (20.95±1.39 vs. 24.09±0.81mg/ml in groups without Ob, p < 0.05). Distribution of the disease by the degree of provision of vitamin D showed that in a cohort with low security vitamin D and the presence of Ob subgroup with a deficiency of vitamin D (20–29ng/ml) was almost twice as large as the similar subgroup without Ob. As follows, the presence of Ob in patients with endocrine pathology has no probable effect on the incidence of hypercalcemia, but is associated with a probable decrease in the level of vitamin D in the blood with a predominance of subgroups with vitamin D deficiency, while in the group without Ob. Conclusions. In the climatic conditions of Ukraine and the functioning health care system in patients with endocrine pathology, the average level of vitaminD is within its deficiency (22.95±0.73 ng/ml). The presence of obesity in patients with endocrine pathology is associated with a probably lower supply of vitamin D, almost doubling the subgroup with vitamin deficiency (<20ng/ml). The combination of obesity and vitaminD deficiency should be considered as a risk factor for primary hyperparathyroidism in patients with endocrine pathology. Such patients need regular monitoring of blood calcium and parathyroid hormone, as well as medical support for vitamin D.