Introduction. The presence of obstructive sleep apnea (OSAS) in patients with chronic heart failure (CHF) increases cardiovascular and overall mortality in comparison with patients without breathing disorders during sleep.Aim of study. Assessment of prevalence and dynamics of OSAS in patients with CHF due to rheumatic heart disease (RHD).Materials and methods. The study included 172 patients with RHD. OSAS was assessed using a cardiorespiratory monitor “Kardiotekhnika-04-3Р (M)”.Results and discussion. Analysis of echocardiography results of showed a significant increase in the linear dimensions of the LV: for LVED B = 0.020 (0.013; 0.027), p = 0.001, R2 = 0.087; for LVES B = 0.017 (0.010; 0.024), p = 0.001, R2 = 0.073. An increase in the indices of hypertrophy was also revealed – LVPW and IVS: for IVS B = 0.008 (0.006; 0.010), p = 0.001, R2 = 0.148; for LVPW B = 0.006 (0.004; 0.08), p = 0.001, R2 = 0.087. The highest values of echocardiography indicators were achieved in the group with OSAS III, in comparison with patients without OSAS. significantly differed: for LVED – 0.86 cm, for LVES – 0.56 cm, for IVS – 0.41 cm, for LVPW – 0.34 cm. but there was also the maximum distance of the 6-minute walk test – 390.02 (360.15; 419.88) meters. Assessment of the quality of life according to the summary scales of the questionnaires showed a higher level of quality of life in the group without OSAS according to the physical health SF-36 (B = -0.100 (-0.169; -0.031), p = 0.005, R2 = 0.029), mental health SF-36 B = 0.120 (-0.091; 0.115), p = 0.821) and according to overall summary score KCCQ (B = -0.289 (-0.473; -0.105), p = 0.002, R2 = 0.036).Conclusion. In the dynamics over 10 years, in patients with RHD, there was an increase in the number of episodes of obstructive and central apnea, an increase in the frequency of episodes of apnea / hypopnea with desaturation and snoring. However, a significant increase was achieved only in the case of obstructive sleep apnea episodes – by 14.60 episodes.