Objective: Patients with comorbid diagnoses of a substance use disorder and at least one other axis I mental disorder have low rates of compliance with aftercare. The purpose of the study was to identify predictors of noncompliance among dual diagnosis inpatients. Methods: Characteristics of 48 dual diagnosis inpatients were examined. Compliance was defined as visiting the aftercare site at least three times. Results: Persons with a diagnosis of cocaine dependence were significantly more likely to be noncompliant with aftercare than those with a diagnosis of cocaine abuse. Patients with a discharge diagnosis of any type of depression were more likely to be noncompliant than those without such a diagnosis. During inpatient treatment, patients who were subsequently noncompliant with aftercare showed more erratic patterns of privilege loss and gain. Conclusions: Knowledge of factors related to noncompliance with aftercare may lead to better intervention with dual diagnosis patients.