Colorectal cancer is still a majorhealth and social problem. However, many important advances in treatment have been made in the last 4 to 5 years, and more optimism is now justified both among clinicians and patients. In surgically resectable disease, adjuvant chemotherapy has been clearly demonstrated as able to increase overall survival in patients with colon cancer Dukes' stage C, whereas the role of medical treatment in patients with Dukes' stage B colon cancer is still controversial. At present, the standard regimen is bolus fluorouracil (5-FU) modulated by folinic acid (leucovorin) for 6 months. For rectal cancer, the best adjuvant treatment seems to be represented by radiotherapy (better if administered preoperatively) combined with chemotherapy (usually based on modulated or continuously infused 5-FU). In advanced disease, many new drugs have recently emerged: the most active regimens are those combining an optimal modality of 5-FU administration (i.e. continuous infusion) and one of the most active innovative compounds (irinotecan or oxaliplatin). The role of the oral drugs (e.g. tegafur/uracil, capecitabine) is still under investigation as is the combination of agents excluding 5-FU. It is now recognised that first-line treatment must be offered to all suitable pa- tients, even though asymptomatic, and that a second-line therapy (chiefly with irinotecan) is of value in many patients with cancer that progresses during treatment with 5-FU. From a strategic point of view, the best sequence of drugs/regimens has not yet been defined, while the duration and timing of chemotherapy is still a matter for clinical research. Finally, there is an increasing interest in the role of biological prognostic factors as an aid to a patient-tailored therapy, both in the adjuvant setting and in advanced disease. To achieve further progress in knowledge in this field, we strongly recommended that more and more patients are included in clinical trials.