Background/Aims: A single-center, prospective observational study was performed to evaluate outcomes in patients undergoing D2 or D3 lymphadenectomy for gastric cancer. Methodology: Lymphadenectomies were performed according to the classification published by the Japanese Gastric Cancer Association. Results: Of 468 consecutive patients, 370 underwent D2 and 98 underwent D3 lymphadenectomy. Postoperative complications were significantly less common in the D2 group than in the D3 group (19.2% vs. 35.7%, p=0.001). Postoperative mortality in the two groups was similar, being 3.8% in the D2 group and 5.1% in the D3 group (p>0.05). Median postoperative survival times were also similar, in the D2 group being 37.8 months (95% CI: 23-52.5), and in the D3 group 30.2 months (95% CI: 13-47.3, p>0.05). Conclusions: In patients who underwent gastrectomy with curative intent, lymphadenectomy that was more extensive than D2 did not provide a survival benefit compared to D2 dissection.