The All New Zealand Acute Coronary Syndrome Quality Improvement programme (ANZACS-QI) uses a web-based system to create a clinical registry of patients with acute coronary syndrome (ACS) and other cardiac problems admitted to hospitals across New Zealand. This detailed clinical registry is complemented by parallel analyses of, and individual linkage to, New Zealand's multiple routine health information datasets. The programme is primarily designed to support secondary care clinicians to implement evidence based guidelines and to meet national performance targets for New Zealand cardiac patients. ANZACS-QI simultaneously generates a large-scale research database and provides an electronic data infrastructure for clinical registry studies. ANZACS-QI has been successfully implemented in all the 41 public hospitals across New Zealand where acute cardiac patients are admitted. By June 2015 25,273 patients with suspected ACS and 30,696 referred for coronary angiography were registered in ANZACS-QI. In this report we describe the development and national implementation of ANZACS-QI, its governance, the data collection processes and the current ANZACS-QI cohorts and available outputs.