The Los Angeles Bureau of Sanitation (Bureau) faces a potential loss of critical "corporate" knowledge as more than 60% of its workforce will be eligible to retire in the next five years. Rather than ignoring its aging workforce, the Bureau has taken steps to avoid significant impacts from this looming loss of knowledge. In any knowledge retention approach, many dilemmas must be understood and managed before and during implementation. One of these major dilemmas is whether to focus knowledge retention strategy on people or information technology. The Bureau recognized that an over reliance on technology could create or reinforce silos in the organization whereas a people approach can be limiting in its reach across the organization. An initial step was taken in Spring 2006 to address the Bureau's knowledge retention situation and map out a strategy to retain knowledge critical to the its operations. This paper presents the steps taken to identify critical knowledge at risk of being lost by the Bureau and the approach recommended to avoid that loss. Steps in the approach included: a series of focus groups for key stakeholders to identify the types of critical knowledge at-risk within the Bureau, as well as existing programs and practices in place to stem the loss of that critical knowledge; a workshop with executive management to differentiate "critical" knowledge from "important" knowledge; and, development of a knowledge retention strategy based on the following four point framework - human resource policies and procedures, knowledge transfer practices, information technology applications to capture, store, and share knowledge, and knowledge recovery initiatives. In this process, care was taken to recognize that a successful strategy must be multifaceted. Effective solutions employ not only information technology tools, but also social networks and policies/procedures. The Bureau has embarked on its knowledge retention strategy and will take steps in the next fiscal year to address the most critical knowledge at-risk of being lost. Other steps will be taken over the following five years to be more prepared for the retirement of more than half of its workforce. Includes reference, figures.