A sample of Belgian drug-involved inmates (N=116) completed the European Addiction Severity Index, the Raven Standard Progressive Matrices (SPM), and the Circumstances, Motivation, and Readiness Scales. The pilot results demonstrate that nearly 50% of the participating drug-involved offenders display low intellectual abilities (SPM score definitely below average). Legal difficulties, drug abuse, and psychological problems are identified as the most severe problem areas for the total group. The participants display low to moderately low scores regarding motivation, readiness, and external reasons to stay in or leave treatment. No to very limited correlations between motivational attributes and other variables such as the length of the prison sentence and the number of violent crimes are found. Participants with high intellectual abilities are less motivated to enter substance abuse treatment compared to their counterparts with average and low intellectual abilities. Implications for treatment are discussed.