Extracardiac rhabdomyoma is a rare benign tumor of striated muscle origin which is mostly located in head and neck areas. Only four cases of adult rhabdomyomas in the mediastinum have been reported and these cases were diagnosed on surgical excision or autopsy. We report the clinical and cytological findings of a mediastinal rhabdomyoma which has been diagnosed by transesophageal endoscopic ultrasound-guided fine needle aspiration (FNA). FNA showed loose aggregates and isolated large round to polygonal tumor cells with abundant granular cytoplasm. Immunostains on the cell block showed strong positivity of tumor cells for myoglobin and desmin. This report highlights the cytologic diagnosis of this rare entity and its potential differential diagnosis.