Purpose: This study was conducted to investigate the incidence, associated factors and clinical impact of hyperamylasemia in self-poisoning patients. Methods: This study was based on a toxicology case registry of patients treated from 2009 to 2013 at a tertiary care university hospital. We retrospectively investigated the demographics, clinical variables, laboratory variables and intoxicants. Hyperamylasemia was defined as an elevation in serum amylase level to above the upper normal limit within 24 hours after admission. We analyzed the predisposing factors and clinical outcomes of patients in the hyperamylasemia group. Results: Hyperamylasemia was identified in 49 (13.3%) of the 369 patients. Using multivariate logistic regression, the odds ratios for HA were 3.384 (95% confidence interval, 1.142-8.013, p=0.014), 3.261 (95% confidence interval, 1.163-9.143, p=0.025) and 0.351 (95% confidence interval, 0.154-0.802, p=0.013) for pesticides, multi-drug use and sedatives, respectively. In the hyperamylasemia group, the peak amylase levels during 72 hours were correlated with the peak lipase levels (r=0.469, p=0.002) and peak aspartate aminotransferase levels (r=0.352, p=0.013). Finally, none of these patients had confirmed acute pancreatitis. Conclusion: Hyperamylasemia occurred rarely in these self-poisoning patients, and pesticide and multi-drug use were independent predictors of hyperamylasemia. Peak amylase levels were correlated with the peak lipase and aspartate aminotransferase levels.