To describe the Italian Obstetric Surveillance System (ItOSS) investigating maternal death through incident case reporting and confidential enquiries.All maternal deaths occurred in any public and private health facility in 8 Italian regions covering 73% of national births have been notified to the ItOSS. Every incident case is confidentially reviewed to assess quality of care and establish the cause and avoidability of the death.A total of 106 maternal deaths among 1 455 545 live births have been notified to the surveillance system in 2013-17. Haemorrhage, sepsis and hypertensive disorders of pregnancy are the leading causes of direct maternal deaths due to obstetric causes.A maternal mortality surveillance system, including incidence reporting and confidential enquiries along with a retrospective analysis of administrative data sources, emerged as the best option for case ascertainment and for preventing avoidable maternal deaths.