Background: The oxaliplatin-based therapy administerated over 6 months remains the standard of adjuvant treatment for stage III colon cancer patients.The IDEA study demonstrated that in certain substages (T1-3N1) 3-month therapy was nearly as effective as 6 months, and less toxic. In MOSAIC, NASBP-C07 and NO16968 studies, round 30% of patients didn‘t complete oxaliplatin-based therapy due to side effects.The cumulative-doses of oxaliplatin in MOSAIC and NASBP-C07 were lower than planned. We evaluated retrospectively the correlation between the cumulative-dose of adjuvant oxaliplatin and the clinical outcomes in stage III colon cancer patients. Methods: Retrospective analysis included III colon cancer patients managed between 2000 and 2014, with surgery and adjuvant chemotherapy using single-agent fluoropyrimidines (continuous 5-FU infusion with leucovorin or oral capecitabine) or oxaliplatin-based regimens (FOLFOX-4 or XELOX). Results: Study group included 620 patients (age 25-85 years), 67% pT3, 62% pN1a-b. Oxaliplatin-based and single-agent fluoropyrimidine chemotherapy was administered to 365 (59%) and 255 (41%) patients, respectively. The median follow-up in both groups was 53 months (4.8-192) and 52 months (8.2-115), respectively. In 71 patients (19%) the oxaliplatin treatment was prematurely terminated due to adverse events. The median oxaliplatin dose was 1666 mg/m² (SD 1309-1897 mg/m²). In the multivariate analysis variables correlated with lower probability of relapse included oxaliplatin-based chemotherapy (HR = 0.57, p = 0.023), higher number of removed lymph nodes (HR = 0.95, p = 0.019 and patient age (HR = 0.97, p = 0.05, respectively). Oxaliplatin-based chemotherapy correlated with increased overall survival (OS) in the univariate analysis (HR = 0.63, p = 0.000) but not in multivariate analysis. The cumulative-dose of oxaliplatin did not correlate with disease free survival and OS (HR = 1.00, p = 0.57 and HR = 1.00, p = 0.17). Conclusions: The adjuvant oxaliplatin-based therapy in stage III colon cancer is associated with lower risk of relapse compared to non-oxaliplatin regimens. The cumulative dose of oxaliplatin doesn’t seem to significantly impact treatment outcomes.