Colon cancer is one of the most common malignant tumors in the world. This type of cancer is the second in appearance to people of both sexes in Croatia. Colon cancer or colorectal cancer affects the appendix, large intestine and the terminal part of the large intestine. The colon is part of the digestive system and its main function is to receive chyme, the mix of digested food from the small intestine, and further digest it into a firm stool that passes from the body. The colon must reabsorb water and electrolytes to form a stool. There are several risk factors that might increase a person’s chance of developing colorectal polyps or colorectal cancer such as: excessive consumption of red meat, chronic inflammatory diseases of the colon, such as ulcerative colitis and Crohn’s disease, and a personal or family history of colorectal cancer or colorectal polyps. The course of colon cancer develops more slowly, so the symptoms of cancer are more difficult to recognize in the initial stage of the disease. Blood in the stool, changes in the stool, abdominal pain, cramps, loss of appetite and reduced weight loss are classified as the main symptoms of this disease. Treatment is surgical along with other treatment methods (chemotherapy, radiation). The patient, who has been diagnosed with cancer, will need psychological support. This help can be provided to him by a person who has completed her studies in nursing. Anxiety, depressive states, lack of motivation for treatment and struggle for one's own life are common conditions present in patients. Therefore, psychological support for the patient and the family is extremely important.