Background: There is concern about widespread medication use by people with intellectual disability (ID), especially psychotropic and anticonvulsant agents. However, there is sparse information on prescribing patterns in Australia. Method: This cross-sectional study was conducted between 2000 and 2002 among adults with ID who live in the community in Brisbane, Australia. Medication data were extracted from a health screening tool. Demographic and medical data were collected from telephone interviews and medical records. Results: Of 117 participants, 35% were prescribed psychotropic medications, most commonly antipsychotics, and 26% anticonvulsants. Complementary medications (vitamins, minerals, amino acids, fish oil, and herbal products) were used by 29% of participants. After adjusting for potentially confounding variables, psychotropic medication use was significantly associated with having a psychiatric illness (adjusted odds ratio = 4.6, 95% CI [1.0, 20.6]) and challenging behaviours (4.4, [1.1, 17.3]). Conclusions: People with ID use a broad range of medications. Psychotropic medications continue to be the most predominant agents prescribed for this population. Psychotropic medication use is positively associated with having a psychiatric illness and challenging behaviours.