Background and Objectives : Papillary thyroid carcinoma(PTC) frequently metastasize to the regional neck, however, lateral neck lymph node metastasis is less common. The aim of this study is to investigate clinical and immunohistochemical features of PTC with lateral LN metastasis, and determine the predictive factors for lateral LN metastases. Material and Methods : We undertook a retrospective study of 83 patients treated between January 2007 and December 2009 for PTC by thyroidectomy with or without lateral neck dissection. The following criteria were used to study the clinical predictive value of lateral LN. metastases : sex, age, tumor size, multifocality, extracapsular spread(ECS) and lymphovascular emboli. Immunohistochemical staining for VEGF-A, VEGF-C, Bax, Bcl-2, Cyclin D1, Cyclin E, $p27^{kip1}$ and $p57^{kip2}$ was performed, and quantified blindly by three pathologists who had no clinical information of the patients. Immunohistochemical expression was scored as high(>50% of cells stained) or low(0-49%). Results : With use of univariate and multivariate analysis, tumor size(>2cm) and ECS were independent correlates of lateral LN metastasis in PTC. Expression of VEGF-C, Bax, and Cyclin D1 in the PTC with lateral LN metastasis was scored higher than in PTC without lateral LN metastasis(p<0.05). Conclusion : The important risk factors for lateral LN metastasis in PTC are primary tumor size and the presence of ECS. And expression of VEGF-C, Bax and cyclin D1 may be considered of lateral LN metastatic potential in PTC.