Abstract Background Whether or not to perform prophylactic central lymph node dissection (CLND) in the case of clinically node-negative papillary thyroid cancer (PTC) is controversial. The purpose of this study was to investigate the risk factors for recurrence in clinically node-negative PTC patients who underwent total thyroidectomy plus bilateral central neck dissection and was verified pathologic N1a. Methods We retrospectively reviewed the medical records of 1082 PTC patients who underwent total thyroidectomy and prophylactic bilateral CLND between January 2004 and December 2012. We used Cox-proportional hazard regression analyses in order to explore potential predictive factors for recurrence. Results During a median follow-up (range) of 78 (12–158) months, recurrence occurred in 62 (5.7%) patients. Main tumor size more than 1 cm, gross extrathyroidal extension (ETE), positive lymph node (LN) more than 3, and LN ratio > 0.5 were all significantly associated with recurrence according to univariate analysis. In model I multivariate analysis (tumor size, gross ETE, LN ratio), LN ratio > 5 (hazards ratio [HR], 4.794; 95% confidence interval [CI], 2.674–8.595; p