AIMS: Length of hospital stay (LOS) for acute coronary syndrome (ACS) has important clinical and cost implications. We report recent trends and predictors of ACS hospitalisation LOS in New Zealand. METHODS: Using routine national hospitalisation datasets, we calculated mean LOS for ACS admissions annually from 2006 to 2016, by demographics, ACS subtype and ACS procedures (coronary angiography, percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG)). We also identified predictors of longer LOS. RESULTS: Among 185,962 ACS hospitalisations, mean LOS decreased from 7.8 to 6.7 days between 2006 and 2016 (adjusted decrease = -0.18 days/year). Decline in LOS was observed for all demographic subgroups by age, sex, ethnicity and deprivation quintile. While coronary angiography and PCI rates increased during this time, LOS declined for all management strategies. However, the adjusted rate of decline was greater for patients receiving coronary angiography without revascularisation (-0.24 days/year), PCI (-0.22 days/year) and CABG (0.33 days/year)-than those not receiving angiography (-0.14 days/year), P<0.001. A greater decline occurred for NSTEMI and STEMI (9.4 to 7.5 days and 7.8 to 6.2 days, respectively) than UA (5.4 to 4.9 days). Predictors of longer LOS in 2016 were older age, female, Maori or Pacific ethnicity, not receiving coronary angiography, initial presentation to a non-interventional hospital and CABG. CONCLUSIONS: Mean LOS for ACS hospitalisations declined between 2006 and 2016. The decline was greatest in the increasing proportion of patients who received a coronary angiogram. Further reductions in LOS may be achieved by implementation of nationally agreed pathways for adequate and timely access to coronary angiography.