Background <p>The oncologic impact of D3 lymph node dissection (LND) for colon cancer (CC) has been reported to be favorable. However, D3 LND is potentially more invasive than non-D3 LND, and whether it is beneficial for elderly patients with CC remains unclear. This study aimed to evaluate the perioperative safety and short- and long-term oncologic outcomes of D3 LND in elderly patients with CC.</p> Methods <p>Subjects were 442 elderly patients aged ≥ 70 years who underwent curative surgery for pathologic stage (pStage) I−III CC between 2011 and 2022. Background clinical factors and short- and long-term outcomes were compared between patients who received D3 LND (D3 group; <i>n</i> = 363) and those who received non-D3 LND (non-D3 group; <i>n</i> = 79).</p> Results <p>The D3 group had a significantly higher number of retrieved lymph nodes (median 20 vs. 12, <i>p</i> &lt; 0.001) and a lower rate of postoperative complications (18% vs. 32%, <i>p</i> = 0.040) than the non-D3 group. In the overall cohort, overall survival (OS) did not differ between the two groups. Among pStage III patients, however, OS was significantly better (69.8% vs. 34.1%, <i>p</i> = 0.028), and RFS tended to be better (60.7% vs. 42.6%, <i>p</i> = 0.075) in the D3 group than in the non-D3 group. Multivariable analysis revealed that D3 LND was independently associated with better OS (HR 0.477; 95% CI 0.245–0.931, <i>p</i> = 0.030) and tended to be associated with better RFS (HR 0.588; 95% CI 0.329–1.051, <i>p</i> = 0.073).</p> Conclusion <p>D3 LND is safe and effective in improving the prognosis of elderly patients with pStage II/III CC.</p>