In brief: In these case reports of two highly trained runners, deep vein thrombosis (DVT) was initially diagnosed as an intramuscular hematoma and a Baker's cyst. Both runners responded well to anticoagulant therapy and were able to resume their training programs. Even though otherwise healthy, conditioned patients are not typical candidates, the authors urge that DVT be considered in the differential diagnosis of athletes with leg pain or swelling because of the threat of pulmonary embolism.