Dilation of malignant esophageal strictures often is required to complete staging by endoscopic ultrasound (EUS). This study was designed to determine the successful dilation rate (ability to complete staging) and complication rate of through-the-scope (TTS) balloon dilation for malignant esophageal strictures during EUS. We retrospectively reviewed EUS reports for all cases of primary esophageal cancer staged at five centers between January 2002 and October 2004. All dilations were performed with TTS balloons. Among 272 endoscopic ultrasounds, dilation was required in 77 (28%) and was successful in 73 cases (95%). There was one esophageal perforation after dilation (1.3%; 95% confidence interval (CI), 0.2-7) and one esophageal perforation after EUS without dilation (0.5%; 95% CI, 0.1-2.8; P = 0.48 by two-sided Fisher exact test). There were no other major complications. TTS balloon dilation is highly successful in permitting complete staging of obstructing tumors. The rate of complications after dilation with a TTS balloon dilator is low and similar to the baseline rate of EUS in this setting.