<div><p>Stress-related cardiomyopathy can develop during the postoperative period due to surgery-related stress factors. However, the prevalence and risk factors for this condition are not yet known. During a retrospective, observational study, patients older than 19 years who underwent procedures from January 2011 to December 2015 at a tertiary hospital were included. The main aim was to identify the prevalence and related risk factors for postoperative stress-related cardiomyopathy. To estimate the incidence per risk factor, univariate and multivariate Poisson regression analyses were performed. During the 5-year period, 95,840 patients older than 19 years underwent 125,314 procedures, and the prevalence of postoperative stress-related cardiomyopathy was 17.74 per 100,000 (95% confidence interval, 9.31–26.17), with an in-hospital mortality of 23.5%. As a result, three risk factors were significantly associated: preoperative American Society of Anesthesiologists classification (incidence rate ratio, 5.901 for American Society of Anesthesiologists class 1–2 [ref] versus 3–6; 95% confidence interval,1.289–27.002; <i>P</i> = 0.022); preoperative body mass index (incidence rate ratio, 1.247 for increases of 18.5 [ref] to 30; 95% confidence interval, 1.067–1.458; <i>P</i> = 0.006); and preoperative serum sodium (incidence rate ratio, 0.830 for each increase of 10 mmol/L from 130; 95% confidence interval, 0.731–0.942; <i>P</i> = 0.004). The incidence rate ratio for age for each increase of 10 years from 50 years was 1.057, but it was not statistically significant (<i>P</i> = 0.064). Our study found that the prevalence of postoperative stress-related cardiomyopathy was 17.74 patients per 100,000 adult patients over the course of 5 years, with four cases of in-hospital mortality. Factors that increased the risk of postoperative stress-related cardiomyopathy included higher American Society of Anesthesiologists class (≥3), preoperative hyponatremia, and higher preoperative body mass index.</p></div