Esophageal cancer is frequently associated with squamous cell carcinoma in the head and neck. Both cigarette smoking and alcohol consumption are risk factors for multiple cancers of the head and neck, as well as the esophagus. Routine screening and close follow-up for second cancers are important in patients with esophageal cancer or head and neck cancer. For this purpose, endoscopy with Lugol's staining, as well as narrow-band imaging combined with magnifying endoscopy, is a powerful tool for the early detection of esophageal cancer. Multimodal therapy is essential for patients with double cancers. When considering surgical treatment, the curability of both cancers must be carefully evaluated. If both tumors are potentially curable, each lesion should be treated individually. In patients with metachronous double cancers, the prior treatment of the first primary carcinoma often affects the treatment of the second cancer. Close cooperation among medical staff members is essential for complicated surgeries for double cancers. Techniques that are appropriate for each case must be adopted, such as careful dissection, staged operations, muscular flaps and microvascular anastomosis.