Reports of needle tract seeding (NTS) as a complication of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) have been increasing. To date, most of the reported cases of NTS have been diagnosed during the postoperative follow-up period. Herein, we report a case of NTS that occurred during preoperative neoadjuvant chemotherapy after EUS-FNA for resectable pancreatic cancer. The patient underwent transgastric EUS-FNA for a pancreatic tail tumor. He was diagnosed as having resectable pancreatic cancer and received preoperative neoadjuvant chemotherapy. After completion of the chemotherapy, computed tomography showed a thick-walled cyst-like structure appearing between the pancreas and the gastric wall. Combined resection revealed adenocarcinoma invasion into the cyst-like structure. Based on the clinical course, and surgical and pathological findings, the condition was diagnosed as NTS. It is thus crucial that after EUS-FNA, a detailed review of the imaging findings be conducted in the preoperative period. If adhesions between the stomach and the pancreas are observed after transgastric EUS-FNA, combined resection of the gastric wall should be considered.