Medication errors have long been a barometer of quality in the health care arena. A review of medication errors in community residences for individuals with mental retardation managed by one agency was performed. Medication errors were analyzed and compared to data in the literature. Although the frequency of medication errors in these residential settings was less than medication errors in hospital settings, there is concern about how common the medication error experience is: 85% of residents experienced at least one reported medication error. The number of medications administered to residents also doubled in one year. As this population ages, experiences more complex health problems, and takes more medication, medication administration practices will require systematic monitoring.