Background and Objectives: Most thyroid cancers progress slowly, have high survival rates, and have good prognosis. Therefore, the management of patients with thyroid cancer should be viewed from a long-term perspective, taking into account a return to normal social life. Cancer patients have a higher risk of unemployment than the general population, and so unemployment can be an economic problem for thyroid cancer patients. However, there have been few studies on factors affecting return to work in thyroid cancer patients. The purpose of this study is to investigate occupational changes and the period of leave of absence for patients with thyroid cancer and to identify factors that affect the return to work after surgery. Materials and Methods: A total of 427 questionnaires of thyroid cancer patients were used for the analysis. The occupational changes and sick leave periods were analyzed according to general characteristics, disease-related characteristics, and side effects. Results: The factors related to occupational change and leave of absence in thyroid cancer patients were sex and type of occupation. Women had more occupational changes and longer leave of absence than men, office workers had the least change in occupation, and professional workers had a longer period of sick leave. Fatigue was the primary side effect that affected the leave of absence. Conclusion: Occupation is very important in the life of a thyroid cancer patient. Informing the patient of possible complications and planning proper leave of absence will help the patient return to work and improve the quality of life.