PURPOSE: The purpose of this study was to identify factors that influence medication adherence in colorectal cancer patients receiving oral chemotherapy. METHODS: One hundred and nine colorectal cancer patients receiving oral chemotherapy were recruited in the cross-sectional survey design. A survey including medication adherence, knowledge about chemotherapy, self-efficacy, depression and symptom experience were completed. RESULTS: The level of medication adherence was 7.38+/-.80. Medication adherence showed significant differences according to perceived health status and combination of IV chemotherapy. Medication adherence was significant correlated with self-efficacy, depression and symptom experience. On stepwise regression analysis, the most important factors related to the medication adherence were symptom experience, perceived health status and combination of IV chemotherapy. These variables explained 17% of medication adherence. CONCLUSION: The level of medication adherence in colorectal cancer patients receiving oral chemotherapy was relatively high. It is important to develop nursing intervention for medication adherence in colorectal cancer patients that focus on symptom experience and to consider about perceived health status and combination of IV chemotherapy.