This report presents a practical process for determining an agency's full costs associated with performing highway maintenance. The process can be applied to any specific maintenance activity and ensures that the resulting full cost incorporates a fair share of both maintenance program and enterprise support costs. In addition, the report documents the application of the full cost determination process for a number of state departments of transportation and different maintenance activities to demonstrate the types of options, exceptions, and decisions that would be needed in order to perform the full cost calculation. The material contained in the report should be of immediate interest to state maintenance engineers and others involved in the maintenance of highway infrastructure.