This study aimed to estimate the cumulative direct criminal justice system costs incurred by age and offending year between 1975 and 2004 by a cohort of women with a co-occurring substance abuse and mental disorder (COD) placed in a compulsory treatment facility for substance abuse between 1997 and 2000. Official register data were obtained for the period 1975–2004 on criminal charges, prosecutions, judgments and sentences by a consecutive sample of 227 women. The 2010 unit price data were applied to resource use and total costs were calculated and reported by age and offending year. A total of 211 women (92.9%) were charged for at least one crime during the period under review. The mean length of criminal career was 8.58 years. Theft and narcotics offenses were the crime categories with the highest number of crimes committed and charges made. The total criminal justice system costs per person averaged 834,897 Swedish crowns (SEK, 2010) over the entire sample. This study provides cost data on the real criminal careers of women with COD which can be used to estimate the potential benefit of targeted interventions at various stages in an individual's criminal career. The results indicate that early, targeted, effective intervention can have substantial benefits.