The purpose of this study was to identify the frequency of chemotherapy-induced amenorrhea and associated factors thereof in premenopausal female patients diagnosed with colon cancer. Premenopausal female patients under the age of 50 years who were diagnosed with stages I, II, and III colon cancer were included. A questionnaire surveying personal history including menarche, comorbidities, drugs, other clinical features, and menstrual history during and after completion of chemotherapy was filled by the patients during outpatient visits. Patients who received pelvic radiotherapy were excluded from the study. A total of 60 patients were included in the study. Eleven patients had been treated with surgery alone, and 49 patients had received adjuvant chemotherapy with either fluorouracil (5-FU) alone (n=22) or 5-FU+oxaliplatin (n=27). The frequency of persistent amenorrhea 1 year after receiving chemotherapy was 20% in the whole group, 18% in patients who had received adjuvant chemotherapy with 5-FU alone, and 22% in patients who had received chemotherapy with 5-FU+oxaliplatin. Frequency of persistent amenorrhea was 3.5% in patients under the age of 44 years and 42.8% in patients aged 44 years and older. Multivariate analysis showed that age of 44 years and older (hazard ratio: 29.3; 95% confidence interval: 2.8-309.2, P=0.005) and menarche age of 14 years and older (hazard ratio: 7.6; 95% confidence interval: 1.2-49, P=0.076) were significantly associated with increased risk of persistent amenorrhea. In this study, we found that the frequency of persistent amenorrhea was 20% in patients who received 5-FU monotherapy or oxaliplatin-based adjuvant chemotherapy protocols in colon cancer treatment. Older age and later menarche were the factors that increased the risk of persistent amenorrhea 1 year after chemotherapy.