Home care is one of the fastest growing sectors of the health care field, but recent research has raised safety concerns among patients receiving home services. A prospective cohort study revealed that 10% of home care patients experienced an adverse event, an incidence comparable to that found in hospitalized patients. This study used a Delphi approach to determine the types of adverse events in home care that should be considered serious (in terms of the level of patient harm) and preventable. Four types of serious preventable events were identified: inappropriate client service plans, medication errors requiring emergency treatment, catheter-associated infections, and incidents related to care that did not fall within practice standards. The authors advocate for using this classification scheme as the basis for a home care adverse event reporting system, analogous to state reporting systems for serious errors occurring in hospitalized patients.