Abstract: AIM To study the characteristics of predisposing causes and premonitory symptoms of vasovagal syncope. METHODS Predisposing causes and premonitory symptoms of 167 hospitalized patients with unexplained syncope were analyzed and compared with the results of heat-up tilt testing on the correlation. RESULTS One hundred and twenty (71.8%) patients had a positive result. The most common type of response was mixed type (60.0%), followed by vasodepressor (25.8%) and cardioinhibitory (14.2%) types. Totally, 67.1 % and 93.4 % of the patients with unexplained syncope had predisposing causes and premonitory symptoms. The most common predisposing causes were prolonged standing (42.9%), change of position (21.4%), and hot or warm environments (15.2%). Ten common premonitory symptoms about the vasovagal syncope were dizziness (76.6%), pale (26.9%), hypodynamia (52.6%), nausea or vomiting (44.9%), sweating (46.1%), paraesthesia (14.9%), palpitation (25.1%), amaurosis (22.8%), chest distress (5.9%), and amblyacousia (27.5%). Among patients with a positive response, dizziness (OR: 5.972, CI=2.013-17.453, P=0.001), vomiting (OR: 5.774, CI=1.475-22.611, P=0.012), hypodynamia (OR: 4.048, CI=1.101-14.889, P=0.039), and sweating (OR: 3.36, CI=1.061-10.610, P=0.035) could predict the positive result of HUTT. CONCLUSION Detailed inquiry about predisposing causes and premonitory symptoms is of great help in correct diagnosis of vasovagal syncope.