The purpose of this study was to examine associations between substance use disclosure during the clinical interview and on the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) Substance Abuse Scale (SUB) among forensic inpatients. Of the 223 archival reports reviewed that had MMPI-2-RF data, 69% of the MMPI-2-RF protocols were valid based on standard validity criteria, resulting in a final sample of 154 patients (98 men, 56 women). We found that patients who endorsed alcohol or marijuana use during the clinical interview often concurrently denied substance use on the MMPI-2-RF SUB scale (the opposite was found for prescription drug abuse). We also found that the MMPI-2-RF SUB scale and other MMPI-2-RF externalizing scales were meaningfully associated with concurrent substance use variables from a record review form. Finally, we found that the MMPI-2-RF SUB scale demonstrated incremental validity over other MMPI-2-RF externalizing scales in the prediction of substance use problems. These results highlight the utility of SUB scale and other self-report instruments in assessing substance use problems. (PsycINFO Database Record (c) 2020 APA, all rights reserved).