A low survival rate in patients with cardiac arrest is associated with failure to recognize the condition in its initial stage. Therefore, recognizing the warning symptoms of cardiac arrest in the early stage may play an important role in survival.To investigate the warning symptoms of cardiac arrest and to determine the correlation between the symptoms and outcomes.We included all adult patients with all-cause cardiac arrest who visited Peking University Third Hospital or Beijing Friendship Hospital between January 2012 and December 2014. Data on population, symptoms, resuscitation parameters, and outcomes were analysed.Of the 1021 patients in the study, 65.9% had symptoms that presented before cardiac arrest, 25.2% achieved restoration of spontaneous circulation (ROSC), and 7.2% survived to discharge. The patients with symptoms had higher rates of an initial shockable rhythm (12.2% vs 7.5%, P = 0.020), ROSC (29.1% vs 17.5%, P = 0.001) and survival (9.2% vs 2.6%, P = 0.001) than patients without symptoms. Compared with the out-of-hospital cardiac arrest (OHCA) without symptoms subgroup, the OHCA with symptoms subgroup had a higher rate of calls before arrest (81.6% vs 0.0%, P < 0.001), health care provider-witnessed arrest (13.0% vs 1.4%, P = 0.001) and bystander cardiopulmonary resuscitation (15.5% vs 4.9%, P = 0.002); a shorter no flow time (11.7% vs 2.8%, P = 0.002); and a higher ROSC rate (23.8% vs 13.2%, P = 0.011). Compared to the in-hospital cardiac arrest (IHCA) without symptoms subgroup, the IHCA with symptoms subgroup had a higher mean age (66.2 ± 15.2 vs 62.5 ± 16.3 years, P = 0.005), ROSC (32.0% vs 20.6%, P = 0.003), and survival rates (10.6% vs 2.5%, P < 0.001). The top five warning symptoms were dyspnea (48.7%), chest pain (18.3%), unconsciousness (15.2%), paralysis (4.3%), and vomiting (4.0%). Chest pain (20.9% vs 12.7%, P = 0.011), cardiac etiology (44.3% vs 1.5%, P < 0.001) and survival (33.9% vs 16.7%, P = 0.001) were more common in males, whereas dyspnea (54.9% vs 45.9%, P = 0.029) and a non-cardiac etiology (53.3% vs 41.7%, P = 0.003) were more common in females.Most patients had warning symptoms before cardiac arrest. Dyspnea, chest pain, and unconsciousness were the most common symptoms. Immediately recognizing these symptoms and activating the emergency medical system prevents resuscitation delay and improves the survival rate of OHCA patients in China.©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.