Background: Esophageal cancer has a relatively poor prognosis ( < 15% overall 5-year survival), owing to a lack of initial symptoms and delayed diagnosis. Also, patients with this fatal cancer tend to have a high rate of mental disorders. The psychological problems can affect treatment compliance and could increase mortality in cancer survivors. Methods: The aim of this longitudinal study was to analyze the prevalence of mental disorders in esophageal cancer survivors using claims data in South Korea. We confirmed mental disorders in a nationwide cohort of 8,879 patients who were diagnosed with esophageal cancer between January 1, 2010 and December 31, 2014. We categorized the prevalence of mental disorders based on the age and the time of diagnosis. Results: In esophageal cancer, a total of 738 patients were diagnosed with a mental disorder, 1 year prior to the cancer treatment. Of those patients, 231 were diagnosed with depression (31.3%) and 245 with anxiety (33.2%) during their first visit. The overall frequency of mental disorders peaked within 2 months after the cancer treatment. The highest rate of increase after treatment was confirmed in stress reaction/adjustment disorders. Age and sex was a significant predictive factor for mental disorders (p < 0.05). Female patients were at a higher risk for mental disorders (hazard ratio: 1.30, p = 0.002), whereas patients with initial treatment as surgery were more likely to have mental disorders compared with radiotherapy (hazard ratio: 1.33, p < 0.001). Conclusions: Mental disorders in esophageal cancer survivors showed different patterns of prevalence depending on the nature of disease. Timely diagnosis and intervention for psychological distress could increase the quality of life for esophageal cancer survivors.