Introduction. Blood donation is a voluntary act of giving a portion of blood from a healthy person to diseased with a curative goal. This blood is used during operations and in emergencies accompanied by significant blood loss. As soon as blood donation is connected to functional abilities of cardio-vascular system orthostatic tests are needed in order to evaluate its tolerance to changes without any harm.  Aim of the study. Evaluation the influence of donation on cardiovascular system activity depending on the tone of autonomous nervous system.  Materials and methods. Have been used methods of cardiovascular system function assay, including Valtgofel orthostatic test (hemodynamic stats evaluation) and autonomic nervous system tone evaluation (e.g. Kerdo index, Danini-Ashner reflex). The study was attended by 100 volunteers, who were divided in two groups: 50 volunteers who donated blood in Vinnitsa district blood transfusion center and 50 – control group. Autonomic nervous system and orthostatic test were evaluated in both groups.  Results. Natural reaction to the test was heart rate increasing by 10-16 b/min after the test and heart rate stabilization in a follow up period of 3 min (on the level from 6 to 10 beats per minute higher than in horizontal position). Strong reaction indicates high reactivity of sympathetic part of autonomic nervous system, what is common for untrained people. Weaker reaction is observed in case of low reactivity of sympathetic system and higher tone of parasympathetic part of autonomic nervous system, what usually indicates trained state of cardiovascular system.People with parasympathetic predominance - 11(22%) don’t have any changes in functioning of cardiovascular system (pressure, pulse); 39 volunteers (78%) have sympathetic part of autonomic nervous system predominance: 31 of them (62%) had significant increasing of blood pressure and pulse and 8(16%) had hypertension and pulse increasing.  Conclusions. Blood donation might be a tool for training of cardiovascular system in 22% cases. In 62% of volunteers blood donation is harmless. For 16% of volunteers who has high blood pressure blood donation is dangerous and could be life threatening.