Background An early diagnosis of acute coronary syndrome (ACS) is crucial for treatment and prognosis. The aim of this study was to evaluate the Manchester triage system (MTS) for patients with ACS, e.g. ST-segment elevation myocardial infarction (STEMI), non-ST elevation myocardial infarction (N-STEMI) and unstable angina pectoris (UAP). Methods Retrospective analysis of patients diagnosed with ACS (STEMI, N-STEMI and UAP) who were triaged in the emergency department (ED) with the MTS. Results In this study 282 patients with ACS (STEMI: 34.0%, N-STEMI: 61.7%, UAP: 4.3%) were triaged as MTS level 1 (immediate assessment): 0.4%, MTS level 2 (very urgent): 51.4%, MTS level 3 (urgent): 41.5%, MTS level 4 (standard): 6.7%, MTS level 5 (non-urgent): 0%. We observed significantly lower mean MTS levels in males (male: 2.48 ± 0.59, female: 2.68 ± 0.68, p = 0.02) and in patients younger than 80 years (age <80 years: 2.50 ± 0.61, age ≥80 years: 2.70 ± 0.67, p = 0.03). We did not find a significant difference of mean MTS levels in different types of ACS (STEMI: 2.46 ± 0.6, N-STEMI: 2.59 ± 0.64, STEMI