Summaryobjective (i) To identify clinical causes of maternal deaths at a regional hospital in Tanzania and through confidential enquiry (CE) assess major substandard care and make a comparison to the findings of the internal maternal deaths audits (MDAs); (ii) to describe hospital staff reflections on causes of substandard care.methods A CE into maternal deaths was conducted based on information available from written sources supplemented with participatory observations and interviews with staff. The compiled information was summarized and presented anonymously for external expert review to assess for major substandard care. Hospital based maternal deaths between 2006 and 2008 (35 months) were included. Of 68 registered maternal deaths sufficient information for reviewing was retrieved for 62 cases (91%).As a supplement, in-depth interviews with staff about the underlying causes of substandard care were performed.results The causes of death were infection (40%), abortion (25%), eclampsia (13%), post-partum haemorrhage (12%), obstructed labour (6%) and others (4%). The median time available for hospital staff to manage the fatal complication was 47 h. The CE identified major substandard care in 46 (74%) of the 62 cases reviewed. During the same time period MDA identified substandard care in 18 cases. Staff perceived poor organization of work and lack of training as important causes for substandard care. Local MDA was considered useful although time-consuming and sometimes threatening, and staff dedication to the process was questioned.conclusion Quality assurance of emergency obstetric care might be strengthened by supplementing internal MDA with external CE.keywords maternal deaths, substandard care, delays in emergency obstetric care, maternal death audit, confidential enquiries into maternal deaths, developing world.