Background <p>This study aims to determine the relationship between persistent grade 1 chemotherapy-related oral mucositis and serum amylase level.</p> Methods <p>The study was conducted as a retrospective cross-sectional study. Among the patients diagnosed with cancer whose file information was available, the files of those whose chemotherapy-related oral mucositis status was recorded after the first cycle treatment were examined. Among these patients, those whose serum amylase levels were checked for any reason and those who did not meet the exclusion criteria were included in the study.</p> Results <p>A total of 376 patients were analyzed. It was observed that grade 1 oral mucositis persisted in 44% of the patients. With the ROC curve, the cut-off value for serum amylase level before the second cycle treatment was determined to be 69.5 U/L (AUC 0.771, 95% CI 0.720–0.821, <i>p</i> = 0.00011). The sensitivity rate of serum amylase levels above this value in predicting chemotherapy-associated oral mucositis was 68.29% and the specificity rate was 100%. In univariate and multivariate logistic (binary) regression analysis, it was concluded that high serum amylase level was an independent factor affecting the presence of oral mucositis (OR 3.37, 95% CI 1.94–9.66; <i>p</i> = 0.00014).</p> Conclusion <p>It was concluded that serum amylase level may be an independent predictive factor for determining persistent grade 1 chemotherapy-induced oral mucositis. Original</p>