This chart review study examined identification and treatment of substance misuse on an inpatient psychiatry ward before and after the hospital's administration made changes to increase attention to patients' substance misuse. Before the ward changes, 113 of 250 inpatients (45 percent) were identified as misusing substances. Misusers were significantly more likely to be younger, male, single, and cigarette smokers. After the ward changes, substance misuse was more than twice as likely to be addressed in treatment planning and discharge diagnoses, and referrals to substance abuse treatment were nearly twice as likely to be made. Changes in assessment of and treatment planning for psychiatric inpatients may increase attention to substance misuse.