After consultation with jurisdictions and alcohol and other drug treatment agencies, four new data elements were piloted in three jurisdictions. This bulletin presents the findings of this project.The Enhancement Project of the Alcohol and Other Drug Treatment Services National Minimum Data Set (AODTS-NMDS) examined the feasibility of introducing the components of a statistical linkage key and one or more indicators of mental health comorbidity into the AODTS-NMDS. After consultation with jurisdictions and alcohol and other drug treatment agencies, four new data elements were piloted in three jurisdictions. This bulletin presents the findings of this project.