Background <p>Cancer patients frequently present to the emergency department (ED) with a wide range of acute conditions. Rapid and accurate triage can significantly improve clinical outcomes. This study aimed to evaluate the predictive value and clinical usefulness of the perfusion index (PI), measured using a simple and easily applicable method, for triage and prediction of 30-day mortality in cancer patients.</p> Method <p>This study was retrospective design. Patients who had a history of malignancy and were brought to the ED by ambulance service between January 01, 2019 and December 31, 2022 were scanned from the hospital database. The patient’s clinical, laboratory parameters, and PI at the time of admission were recorded. The patients’ Emergency Severity Index (ESI) and quick Sequential Organ Failure Assessment (qSOFA) values were calculated. The ​​of all patients Patients’ 30-day mortality were recorded. The multivariate logistic regression test was used to examine the factors affecting mortality. A p value &lt; 0.05 was considered statistically significant.</p> Results <p>A total of 208 patients were included in the study. The 30-day mortality rate was 37% (77). In the logistic regression analysis, it was found that the patients in ESI-1,2 had a 6.26-fold (OR: 6.258) mortality (<i>p</i> &lt; 0.001), while we found that PI did not contribute to predicting mortality (<i>p</i> = 0.640). qSOFA value above 2 was found to be superior in predicting mortality with 74.3% AUC, 54.55% sensitivity, 87.79% specificity (<i>p</i> &lt; 0.001).</p> Conclusion <p>The PI was less significant than the high-risk ESI and qSOFA scores for predicting 30-day mortality.</p> Clinical trial number <p>Not applicable.</p>