This article provides a comprehensive review of the outcomes of polypharmacy in nursing homes. Our review had some limitations. First, we only included studies beginning in 1990, and significant earlier studies are not included. Only English language articles were included. We only researched studies from MEDLINE, and may have missed studies based on our search terms and search tools. There are many definitions of polypharmacy in the literature, including number of medications or inappropriate medications. In this review, we defined polypharmacy as a high number of medications, but not inappropriate medications. It was not surprising that polypharmacy was consistently associated with an increased number of potentially inappropriate drugs. The majority of studies were viewed showed that polypharmacy was associated with increased ADEs, increased DDIs, and increased hospitalizations. We were surprised that polypharmacy was not consistently linked with falls, fractures, and mortality. For the mortality studies, it has been postulated that perhaps some patients receiving 10 or more medications may have been moribund or receiving end-of-life or hospice care. It is possible that the number of medications is not as important as the number of potentially in appropriate drugs. There need to be more studies on these outcomes, using different definitions of polypharmacy. Polypharmacy was associated with increased costs. The drug-related morbidity and mortality, including those resulting from inappropriate medications and increased staff time, led to increased costs. Use of consultant pharmacists has been shown to decrease polypharmacy costs.