Aim. To assess manifestation of autonomic cardial neuropathy (ACNP) in type 1 diabetes mellitus using rhythmocardiography method. Materials and methods. The study included 147 patients with type 1 DM, 87 men and 61 women with a mean age of 36,3±13,0 years. Duration and age of DM1 onset was 11,1±10,3 and 24,8±12,3 years. HbA1c – 9,9+2,5%. ACNP diagnosis was confirmed by The Toronto Consensus Panel on Diabetic Neuropathy Criteria with assessment of heart rate variability (HRV) indices using rhythmocardiography (RCG) method and apparatus-program complex “Micor”. The control group included 41 persons. Data processing was performed by means of STATISTICA 6.0 and SPSS 17.0 for Windows. Results. Significant ( p <0,001) fall in HRV indices among DM1patients versus the control was revealed: general variability – SDNN (c) 0,026±0,017 and 0,058±0,01, amplitude of respiratory arrhythmia ARA (c) 0,037±0,03 and 0,095±0,03, root-mean-square deviation in three types of waves – humoral-metabolic σ l (c) 0,015±0,01 and 0,028±0,01, sympathetic σ m (c) 0,012±0,01 and 0,025±0,01, parasympathetic σ s (c) 0,014±0,01 and 0,042±0,02; sample reactivity was decreased. ACNP was diagnosed in 35 (24%) patients including 15 (10%) patients with severe stage 3 ACNP, 10 (6,8%) – stage 2, 12 (8%) – stage 1. Conclusion. Marked disorders of peripheral HRV regulation caused by inhibition of reflex sympathy-parasympathetic regulation in sinus node of the heart were detected with RCG method. ACNP was observed among the most critical patients. The basic factors of ACNP worsening were DM duration and RCG-parameters of reaction to the effect of stimulus.