Intramuscular myxomas (IMM) are rare benign tumors. They tend to involve the muscles of the thigh, buttocks, upper arm, and shoulder. They usually occur in adults between 40 to 60 years old, and they are predominant (>70%) in females. We present a 34-year-old female complaining of a deeply seated mass over anteromedial aspect of her right lower leg for many years. Thelesion seemed to become larger slowly and painful sensation developed over herlower leg recently. Magnetic resonance image (MRI) and sonography were performed at OPD that intramuscular soft tissue lesion was impressed. Sonographically guided needle biopsy for the tumor was undertaken. No malignant cell could be identified by cytopathologic examination. The patient received marginal resection of the tumor. The lesion proved to be an intramuscular myxoma on microscopic examination. She experienced resolution of symptoms after operation. There was no evidence of recurrence at OPD follow up after one year.