Levels II and Vb were involved in a significant number of patients with PTC and lateral neck disease. Younger age and lymphovascular involvement were independent risk factors for level Vb involvement in patients with PTC and lateral neck metastasis. The increased risk might be of marginal clinical significance. No significant predictors were identified for level II involvement. Our findings do not favor a limited neck dissection on the basis of any of the study's clinical or pathologic variables, and we therefore recommend the routine excision of levels IIa to Vb in all patients with PTC presenting with lateral neck disease.