The purpose of this study was to describe the medication management and treatment provided in a specialty outpatient psychiatry clinic for 198 community-residing children and adults with intellectual disability and other developmental disabilities (IDD) referred to the clinic and discharged between 1999 and 2008. Using a descriptive design, data from a retrospective chart audit were examined to explain medication management from referral to discharge. The audit tool collected data on demographic variables, reasons for referral, admission date, clinic appointments, discharge date, diagnoses, and medications. Data on diagnoses and medications were grouped according to categories of the 2000 American Psychiatric Association's DSM-IV-TR: "Diagnostic and Statistical Manual of Mental Disorders," 4th Edition, Text Revision diagnoses and medication classes, respectively. Data were analyzed using descriptive statistics, paired sample t tests, and Wilcoxon signed-rank tests. Interrater reliability was examined with Kappa values and correlation statistics. The study found that psychiatric care in the clinic led to a simplification of medication regimens. For individuals taking prescribed psychiatric medications at referral, psychiatric medication polypharmacy and same-class psychiatric medication polypharmacy were reduced by discharge. Modifications in the profile of medications prescribed generally reflected expert consensus guidelines. The overall findings suggest that this model of provision of specialized psychiatric outpatient services for individuals with IDD may be one approach to improve the quality of mental health care for this underserved population. (Contains 5 tables.)