PURPOSE: This study aimed at examining correlates of substance use among patients diagnosed with psychiatric disorders in Jordan. METHODS: This study used a nonexperimental descriptive survey design. Data were collected through using DUSI-R scale obtained through a self-designed questionnaire. A total of (203) subjects satisfied the inclusion criteriRESULTS: Most used substances prior to admission were caffeine (78.2%), cigarette (60.9%), and alcohol (22.2%), while the least were heroin (1.2%) and inhalants (0.08%). Patients diagnosed with schizophrenia had higher percentages among all other disorders (n = 16, 21.9%), although there was no statistical difference among patients related to their psychiatric disorders. CONCLUSION: We recommend that mental health professionals be equipped with necessary skills to manage substance use among patients with psychiatric disorders.