Small esophageal lesions, particularly intraepithelial cancers, are extremely difficult to detect. We used Lugol's iodine solution with panendoscopic examination to detect the presence and spread of small squamous cell carcinomas of the esophagus. Serial histologic specimens of the surgically removed esophagus from 32 patients with Lugol's combined endoscopic diagnosis of early esophageal carcinoma were examined to determine the correlation between endoscopic and histologic findings. All of the early staged carcinomas clearly remained unstained by Lugol's solution. We believe that the application of Lugol's solution will greatly aid in instances when a suspicious mucosal lesion is noted, when the margin of the lesion is unclear, or when there is suspicion that a mucosal lesion may have been overlooked.