Purpose: Determining pathological nodal stage in patients with bladder cancer is important for prognosis. We determined how the extent of lymphadenectomy and the lymph node count influence accurate nodal staging. Materials and Methods: The study included 120 patients who underwent at least extended lymphadenectomy at radical cystectomy. Different anatomical templates for lymphadenectomy were evaluated for nodal staging accuracy. The cumulative percent was plotted to determine a lymph node count that confidently identified node positive cases. Results: The mean ± SD total lymph node count in the study population was 36.9 ± 14.8 at extended lymphadenectomy. Of the patients 36 (30%) had lymph node metastasis, including 14 (39%) with metastasis involving the common iliac and/or presacral lymph nodes. Limited, standard and extended lymphadenectomy accurately identified 75%, 88.9% and 100% of node positive cases, respectively. Removing 23 and 27 lymph nodes provided 80% and 90% confidence, respectively, that a case was accurately staged as pN0. No patient had lymph node metastasis above the aortic bifurcation without nodal metastasis below the aortic bifurcation and none had a change in pN stage by extending lymphadenectomy above the aortic bifurcation. Conclusions: To accurately identify node positive and negative cases, and correctly assign pN stage in node positive cases it is necessary to perform extended lymphadenectomy. Identifying at least 23 to 27 lymph nodes on final pathological evaluation provides a high level of confidence that a case is correctly staged as node positive or negative. © 2010 American Urological Association.