Colorectal cancer is the second most common malignant disease in developed countries, with about one million new cases worldwide every year, accompanied with high mortality rate. We examined the survival rate and recurrence (occurrence of distant metastases and/or local recurrence) of patients with colorectal cancer in Primorsko-Goranska and Istarska County who received adjuvant chemotherapy, compared to those who did not in the period since 1980. until 1999. This study involves 483 patients with colorectal cancer stages II and III of Primorsko-Goranska and Istarska County, which were underwent curative resections of colorectal cancer at the Clinical Hospital Centre Rijeka, and then treated with chemotherapy (288) or without Chemotherapy (195). We analyzed the five year survival rate and the recurrence of malignant disease in the adjuvant treatment group in comparison with not treated group with chemotherapy, depending on the stage of disease, degree of histological differentiation, patient age and location of cancer (colon or rectum). After follow-up of 60 months died 44.79% (129/288) of patients who received chemotherapy and 53.33% (104/195) of patients who did not receive chemotherapy. The relative risk of death (from any cause) in chemotherapy-treated group versus the group without chemotherapy was 0.82 (p < 0.008). Recurrence of malignant disease in the chemotherapy group was 38.54% (111/288), and in the group without chemotherapy was 46.15% (90/195). The relative risk of recurrence of malignant disease in the chemotherapy group versus the group without chemotherapy was 0.78 (p < 0.001). There was no difference in treatment efficacy regard to the localization of the tumor, but there were differences in efficiency with respect to disease stage, grade and age. Chemotherapy with 5-fluorouracil and leukovorin ameliorate the survival and reduces recurrence and distant metastases in patients with colorectal cancer stages II and III.