We evaluated the relationship between regional lymph node metastasis and tumor size in patients with M0 renal cell carcinoma who received regional lymph node dissection. The study involved 234 of the 247 patients with localized renal cell carcinoma who underwent radical nephrectomy with lymph node dissection at our institute between 1985 and 1999. Patients were arbitrarily classified into 3 groups by the greatest diameter of the tumor on preoperative computed tomography (CT): 4.0 cm or less (group A), 4.1 to 7.0 cm (group B), and 7.1 cm or more (group C). The incidence of lymph node metastasis was assessed in each group. The current study showed that 11 (4.7%) of the 234 patients with lymph node dissection together with radical nephrectomy were lymph node positive. The incidences of lymph node metastasis were 4.0% in group A, 2.3% in group B, and 8.4% in group C (p = 0.79). Of these 11 patients with lymph node metastasis, 2 (18.2%) have so far survived for over 5 years following surgery. Although the role of regional lymph node dissection with radical nephrectomy might be limited and controversial in renal cell carcinoma, urological surgeons should always be aware of possible metastasis for any tumor size.