Background: investigation of disorders in hemodynamic indicators and heart rate variability in children with mitral valve prolapse and functional heart disturbances. Material and methods: The carried out research has included 190 children, at the age from 7 till 18 years: I group 160 (84,2 %) children with mitral valve prolapse I degree, II degree and functional heart disturbances, average age (13,32±0,23) years and II group 30 (15,79 %) healthy children, average age (12,2±0,72) years, with inspection of hemodynamic indicators and parameters of heart rate variability. Results: Results of research have revealed, that syndrome of mitral valve prolapse with functional heart disturbances is accompanied with presence of sympathicotonia an initial vegetative tone in 47,22 % cases and hypersympathicotonia vegetative responsiveness in 42,51 % cases. Conclusions: Mitral valve prolapse find out in children with frequency from 2 % to 16 % of cases, more often at the age from 7 till 15 years with prevalence at girls in a parity (boys, girls 1:2). Results of ECG Holter monitoring 24 hours have established: sinus tachycardia at 72,50 % of children (p <0,01), supraventricular premature contraction at 86,25 % of children (p <0,001). The analysis of spectral parametres of heart rate variability has defined prevalence of spectral parametres of low frequency and very low frequency, that interpret activity of sympathetic nervous system at patients with mitral valve prolapse and functional heart disturbances.