Purpose: We aimed to determine the influencing factors for central neck lymph node metastasis (CLNM) in papillary thyroid microcarcinoma (PTMC) without clinical evidence of metastasis on preoperative ultrasonography. Methods: We retrospectively analyzed 625 patients with PTMC who underwent thyroid surgery at Chosun University Hospital from January 2002 to December 2012. A total of 575 patients who had no evidence of lymph node metastasis by preoperative ultrasonography were included in the study. Medical records, including clinical information and pathologic report, were reviewed. Results: Central lymph node metastasis was found in 81 (14.1%) out of 575 patients. Results of univariate analysis indicated that lymph node metastasis occurred frequently in patients with more than 0.5 cm largest tumor size by preoperative sonography and pathologic reports (P=0.048 and P=0.001, respectively) and lymphovascular invasion (LVI) (P<0.001). Multivariate analysis revealed that sex (female vs. male), pathologic tumor size (0.5-1.0 cm vs. <0.5 cm), and LVI (yes vs. no) were significantly associated with lymph node metastasis (odds ratio [OR], 0.498, 95% confidence interval [CI], P=0.047; OR, 2.450, 95% CI, P=0.005; and OR, 24.954, 95% CI, P=0.007, respectively). Conclusion: Male sex, large tumor size (≥0.5 cm), and LVI were the risk factors for CLNM in patients with PTMC without clinical evidence of node metastasis. Prophylactic central neck lymph node dissection (CLND) might be required in these cases of PTMC.