Objective To describe status on the duration from onset to calling EMS in patients with acute chest pain and to analyze influence factors on delay in calling EMS. Methods Successive 304 patients with acute chest pain, who called EMS in Beijing area and were transported to Peking University People′s Hospital, were included. Data on basic demographic characteristics, treatment time points, medical history, causes and outcomes were collected. The patients were categorized into two groups based on the median duration from onset to calling, and their baseline information was compared. Results Of those 304 cases with chest pain, 151 cases(49.7%)were male, and the median age was 74 years. The chest pain causes of 167 cases(54.9%)were cardiac origin, and 85 cases(28.0%)were acute coronary syndrome. Mortality at emergency department was 8.2%, emergency admission rate was 25.3%, while overall mortality was 9.5%. Pre-hospital time, patient time and EMS transport time were 180 min, 96 min and 63 min respectively. Multivariate Logistic analysis showed that the aged more than 65 years old, calling from urban area, precordial or retrosternal pain and accompanied with fever were associated with delay in calling EMS independently. Conclusion Patients with acute chest pain, especially the aged, suburban residents and patients with coronary heart disease, should be advised to call EMS as soon as possible in order to reduce pre-hospital time.