Substance abusers (SA) usually deny or are not aware that they have a problem. Recent neuro-scientific evidence suggests that denial of problems related to drug use can be associated with alterations in frontostriatal systems, which play a critical role in executive functions and self-awareness. In this study, we examined self-awareness of cognitive deficits, which may be indicative of frontostriatal involvement, in a sample of abstinent SA. We administered the self and informant rating forms of the Frontal Systems Behavior Scale (FrSBe) to 38 SA and to 38 designated informants. We conducted three separate mixed design ANOVAs to contrast the discrepancy between SA and informant scores on the three FrSBe subscales both during drug abuse (assessed retrospectively) and during abstinence. We conducted regression analyses to examine the relationship between severity of drug abuse and self-awareness. Results showed that informants scores were significantly higher than SA s scores on apathy and executive dysfunction during drug abuse, indicating poor awareness of deficits. We found no significant discrepancies between SA s and informants scores during abstinence. Severity of alcohol and cocaine abuse significantly predicted poorer self-awareness during drug abuse, but not during abstinence. These results may have important implications for prevention and treatment strategies.