Indium-111-labeled leukocyte ([111In]WBC) scintigraphy has been used successfully for detection of inflammation. Occasionally, noninflammatory collections of white blood cells such as hematomas or hemorrhage have been localized. We report a case in which unsuspected femoral deep venous thrombosis was diagnosed on an [111In]WBC leukocyte scan performed for detection of osteomyelitis. Readers are advised to avoid interpreting all vascular [111In]WBC localization as necessarily infectious. This may be of particular significance in patients with vascular grafts.