The declining acute coronary syndrome (ACS) incidence has slowed among younger individuals in most ethnic groups, and in older Māori and European individuals, resulting in overall increased inequity for Māori and Pacific peoples, according to a New Zealand population study. First ACS hospitalisations for younger (20-59 years) and older (60-84 years) patients were identified from national administrative datasets for the period 2005 to 2019. The total cohort comprised 69,161 patients, of whom 74.7% were European, 14.2% were Māori and 6.1% were Pacific peoples. Compared with European patients, the ACS incidence rate ratio increased for younger Māori (from 1.5 to 2.25; p=0.017) and Pacific peoples (1.25 to 1.5; p<0.001), and for older Māori (from 1.35 to 1.6; p=0.006) and Pacific peoples (1.0 to 1.6; p<0.001), over the study period.