One of the risk factors that plays an important role in the pathogenesis but is insufficiently studied in the development and progression of hypertension (AH) is the presence of connective tissue dysplasia (СTD). CTD are genetically determined conditions characterized by defects in fibrous structures and the main substance of connective tissue (CT), which lead to disruption of the formation of organs and systems, have a progressive course and determine the features of the associated pathology.The objective: study of the frequency and severity of mitral valve prolapse in patients with hypertension.Materials and methods. We examined 153 patients with primary hypertension I–II stage 1 – 3 degrees (90 men and 63 women) aged 22 to 45 years.Results. Mitral valve prolapse (MVP) was detected in 32 % of patients with hypertension (grade 1 MVP – in 21 % of patients and grade 2 – in 11 %, respectively. The frequency of MVP in stage I hypertension was established than in stage II. MVP with mitral regurgitation of 1–2 degrees was higher in hypertension of stage II in comparison with AH of stage I. MVP of 1 degree was most often associated with increased variability of systolic blood pressure (SBP), and MVP of 2 degree – with increased SBP load and type of daily profile «non-dipper» BP was characterized by a higher incidence of left ventricular hypertrophy (LVH) and supraventricular arrhythmias than in patients without MVP, with an increase in the concentration of free oxyproline in the blood in patients with grade 1 hypertension and total oxyproline – in patients with hypertension with MVP 2 degree.Conclusions. It was found that 32 % of patients with hypertension of young and middle age have MVP 1–2 degrees. An increase in the frequency of MVP in general (1 and 2 degrees) in patients with stage I hypertension, compared with patients with stage II hypertension, as well as the frequency of stage 1 MVP in patients with stage I hypertension compared with patients with stage II hypertension. At the same time, the frequency of MVP 2 degree and MVP with MR 1–2 degree was higher in patients with stage II hypertension compared with stage I hypertension. Patients with hypertension with MVP were characterized by a higher frequency of LVH and the occurrence of supraventricular arrhythmias than for patients without MVP. There was a significant increase in blood levels of free oxyproline in the group of patients with hypertension with MVP 1 degree compared with patients with MVP 2 degree and a significant increase in blood levels of total oxyproline in patients with MVP 2 degree compared with patients with MVP 1 degree.