Currently, source-zone groundwater remediation of a solvent contaminant (primarily trichloroethene[TCE]) is underway at the Naval Amphibious Base Little Creek located in Virginia Beach, Virginia. To better characterize contaminant distribution, assist in remedial design, establish project goals, and provide a benchmark for performance evaluation, a partitioning tracer test (PTT) was conducted in the source-zone prior to initiation of remediation efforts. The PTT is a subsurface characterization technique that allows quantification of nonaqueous phase liquid (NAPL) saturation within the swept volume by evaluating the transport of partitioning and nonpartitioning (i.e., conservative) tracers. To-date relatively few field PTTs have been performed and additional work is needed to identify optimal field application strategies, accurately interpret tracer breakthrough data, and quantify potential error. The results of this PTT are presented and specific field design and data evaluation issues are discussed.