Objective:to identify the occurrence of warning signs and changes in vital signs in individuals who experienced in-hospital cardiorespiratory arrest and correlate them with the occurrence of this event. Method:this is a retrospective, analytical and quantitative study that included 218 medical records of patients who suffered in-hospital cardiorespiratory arrest and identified warning signs and alterations in vital signs. Mean, standard deviation, median, minimum and maximum values were calculated for the continuous variables, and frequency and percentage for the categorical variables. We compared the age and occurrence of cardiorespiratory arrest with the occurrence of warning signs using the Chi-Square Test and the Mann Whitney non-parametric test (p-value < 0.05). Results:62.1% of the patients presented signs and symptoms of shock, 44.9% of neurological alteration, 40.4% of malaise, 15.2% presented signs suggestive of acute coronary syndrome, and 25.9% presented mental confusion. In the last measurement of vital signs before cardiorespiratory arrest, the majority of patients had altered abnormal (32.6%) and severely abnormal (23.9%) heart rate, and abnormal (37.1%) and severely abnormal (27.0%) respiratory rate. Conclusion:the warning signs identified were: shock, neurological signs, malaise and acute coronary syndrome. The prevalent changes in vital signs were: heart rate, respiratory rate and O2 saturation. Patients with severely abnormal systolic blood pressure were not discharged and those with abnormal respiratory rate did not survive 6 months after cardiorespiratory arrest.