This report marks the twentieth anniversary of the Royal Commission into Aboriginal Deaths in Custody (RCIADIC) and thus, 20 years of monitoring deaths in custody by the Australian Institute of Criminology (AIC). Through the National Deaths in Custody Program (NDICP), the AIC has been monitoring the extent and nature of all deaths that have occurred in prison, juvenile justice and police custody since 1992, with data also collected retrospectively back to 1 January 1980. The purpose of this program is to collect information about deaths in custody, analyse the circumstances of these deaths and report findings regularly to the Australian Government. Overall, the NDICP has collected and analysed data on the following cases that occurred between 1 January 1980 and 30 June 2011: 2,325 total deaths in custody across Australia (450 Indigenous deaths; 19%); 1,397 deaths in prison custody (238 Indigenous deaths; 17%); 905 deaths in police and police custody-related operations (204 Indigenous deaths; 23%); 18 deaths in juvenile justice custody (8 Indigenous deaths; 44%); and five deaths in other/Australian Government custody (all non-Indigenous deaths). The data collected in this program are supplied directly to the AIC by police agencies, corrective services departments and juvenile justice agencies in each jurisdiction. Data provided by custodial authorities is supplemented with information obtained through coronial findings, as well as toxicology and autopsy reports. Throughout 2011, the AIC undertook a comprehensive review of the NDICP, which included a focus on data quality, clarifying definitions, improvements to data collection and validation processes, as well as the development of new data on the prevalence of drugs and/or alcohol, and mental illness among those persons dying in custody. To comply with Australian Government reporting practice, the NDICP has moved to reporting on a financial year basis. Analysis of data captured by the NDICP over the last 32 years demonstrates that significant improvements have been made to prevent deaths in some areas, but that work should continue in order to reduce other forms of deaths in custody. This report found that both the Indigenous and non-Indigenous rates of deaths in custody have decreased over the last decade and are now some of the lowest ever seen (0.16 per 100 Indigenous prisoners and 0.22 per 100 non-Indigenous prisoners in 2010?11). For the last eight years, the Indigenous rate of death in prison has been lower than the equivalent non-Indigenous rate. While Indigenous prisoners continue to be statistically less likely to die in custody than non-Indigenous prisoners, there is a concerning trend emerging, as the actual number of Indigenous deaths in prison are rising again, with 14 in 2009-10 which is equal to the highest on record. More concerning still is that over the 20 years since the Royal Commission, the proportion of prisoners that are Indigenous has almost doubled from 14% in 1991 to 26% in 2011.