The current status of treatment for patients with colorectal cancer is suboptimal. Although approximately 80% of patients are amenable to surgery, cure is only possible for 40%. Survival of patients is closely related to disease staging at the time of surgery, being poorer for patients presenting with locally advanced disease or with distant metastases. Patients who undergo curative resections and are categorized as having a high risk of developing recurrence, such as those with regionally involved lymph nodes, should be subjected to studies of adjuvant therapy. Although the definite role of such studies is still under evaluation, there already exist studies of chemotherapy with 5FU, chemoimmunotherapy with 5FU-BCG, and radiation therapy, suggesting the beneficial effect of these treatment modalities based on prolongation of the disease-free interval and survival of patients. The status of available treatments for patients with advanced disease is poor. There exists no single or multidrug regimen capable of producing significant tumor regression to improve the patient's quality of life and survival. Accordingly, the active clinical investigation of newer and potentially effective chemotherapeutic agents should continue. The role of present immunotherapy is not fully determined, although several studies suggest its potential usefulness in the adjuvant and the advanced situations. Serial determinations of CEA are extremely helpful in the postsurgical monitoring of patients receiving adjuvant treatments and also in the follow-up of patients undergoing therapy for overt metastatic disease.