Metastasis of gastroesphageal junction (GEJ) adenocarcinoma in skeletal muscle is rare and primary sites for skeletal muscle metastases are usually lung, renal and colorectal cancer. We have encountered with the first case report of solitary psoas muscle metastasis of GEJ adenocarcinoma. Here we describe a 65 years old man was diagnosed with GEJ adenocarcinoma in Gastroenterology Department, Imam Hussein Hospital, Tehran, Iran in February 2014. We were not able to use PET techniques due to lack of access. Staging CT scans demonstrated a small mass lateral to right psoas muscle. A CT-guided core needle biopsy of right psoas muscle was performed that supported a diagnosis of adenocarcinoma consistent with primary adenocarcinoma of the GEJ. Distant metastasis to skeletal muscle rarely occurs in patients with GEJ adenocarcinoma, but heightened awareness to these soft tissue lesions is warranted. CT or MR imaging could show findings suggestive of metastatic disease, although PET is preferable modality.