We investigated the usefulness of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) for superficial esophageal squamous cell carcinoma after resection via endoscopic submucosal dissection (ESD). Our case study included 37 patients and 49 tumors resected via ESD in our hospital between January 2012 and December 2013. Histopathological diagnosis confirmed squamous cell carcinoma in all cases. Tumors located near the esophago cardiac junction were excluded. We investigated retrospectively whether the standardized uptake value (SUV) obtained by using FDG-PET could be the criterion to decide whether to perform ESD. At first, the tumor was examined via endoscopy. If tumor depth (T status)was less than cSM1, we performed ESD. When the tumor depth was less than pSM1, no infiltration of the vessel or lymph duct was observed, and the surgical margin was free; therefore, we did not perform any further therapy. On the other hand, we measured the SUV obtained via FDG-PET. The cut-off value was set as 3.0 based on the correlation between the SUV and tumor depth. We investigated if SUV<.0 could be the criterion for further therapy after ESD. In our results, the sensitivity was 95%, specificity was 67%, and accuracy was 90%. The SUV also helped to identify the malignancy of the superficial esophageal cancer and could help to decide whether ESD should be undertaken.