Papillary thyroid carcinoma (PTC) is a common thyroid malignancy. Elderly patients have more severe disease and more complications following postoperative endocrine therapy to control thyroid-stimulating hormone (TSH) levels. We aimed to identify optimal postoperative serum TSH levels in elderly patients to prevent recurrence and metastasis and minimize complications. This retrospective cohort study collected data of 87 consecutive elderly patients (age >75) who underwent surgery for PTC with postoperative levothyroxine therapy (50-150 μg/d) between January 2006 and June 2008 and were followed until 2013. After 24 patients with TSH fluctuations and incomplete data were excluded, 73 patients were grouped based on postoperative TSH levels: Group A, 0.3-0.5 mIU/mL; Group B, 0.1-0.3 mIU/mL; and Group C <0.1 mIU/mL (n = 24, 25, 24, respectively). Subjects' baseline, preoperative data, postoperative complications and 1-, 3- and 5-year follow-up data were compared between groups. No significant differences in gender, age (median age of 80 years old), surgery type or clinical characteristics were found between groups (all p value >0.05). Postoperatively, all subjects had normal ECG and neck ultrasound, no osteoporosis, and no differences in survival rate or metastasis. Five-year follow-up revealed significant differences in development of arrhythmias, osteoporosis, insomnia and anxiety between Groups B (0.1-0.3 mIU/mL) and C (<0.1 mIU/mL) compared to Group A (0.3-0.5 mIU/mL). Postoperative incidence of PTC recurrence and metastasis remained stable in elderly patients undergoing thyroid surgery and endocrine therapy but complications increased significantly with increasing TSH levels. Controlling TSH to lower limits of normal may help prevent PTC recurrence and metastasis and reduce complications in this high-risk population.