From 1/1985 to 7/1993, 18 patients underwent endoscopic photodynamic therapy (PDT) for early stage esophageal squamous cell carcinoma -- as two patients had two synchronous esophageal cancers, 20 lesions were treated. Tumors were staged as Tis in 7 cases and T1 in 13. The average light energy delivered was 50 J/cm2 and 70 J/cm2 for the treatment of Tis and T1, respectively. To obtain a more uniform distribution of laser light in 12 cases the irradiation was performed through the wall of a transparent tube previously placed over the endoscope and advanced into the stomach. The overall results show a complete response in 14/20 (70%) tumors. Three patients developed a local recurrence, 6, 12, and 14 months after therapy. After a follow-up of 5 to 75 months, there was no evidence of disease in 10/18 patients (56%). The actuarial survival rate was 95%, 79%, and 26% at 1, 3, and 5 years, respectively. Complications were skin reaction in one patient and esophageal stenosis at the treatment site, that gradually responded to endoscopic bougienage, in 2 patients. Endoscopic PDT proved to be safe and effective in the treatment of superficial carcinoma of the esophagus.