[Excerpt from author]Nurse turnover is a recurring problem for health care organizations. Nurse retention focuses on preventing nurse turnover and keeping nurses in an organization's employment. However, decisions about nurse turnover and retention are often made without the support of full and complete knowledge of their associated costs and benefits. This article identifies common nurse turnover and retention costs and benefits, discusses the use of benefit-cost and cost-effectiveness analysis relevant to nurse turnover and retention, and calls for the construction of a business case for nurse retention. It also provides a foundation for including the costs and benefits of nurse turnover and retention in estimating the economic value of nursing.