Vasovagal syncope is defined as a reflex loss of consciousness related to reaction to various stimuli as orthostatic stress, pain or emotions connected with loss of muscle postural tone. In the second part of the paper the authors describe the possible role of the particular neurohumoral factors and autonomic nervous system in the development of vasovagal syncope. The studies on the involvement of neurohumoral factors in vasovagal syncope can play a key role in a more precise evaluation of affected patients, long term prophylaxis against syncopal events and may contribute to development of more reliable diagnostic tests.