e14692 Background: Colorectal cancer is the fourth cause of cancer in the United States and the third cause of mortality in the same country. In Colombia, it is the fourth most common cancer and the fifth cause of death. Methods: 5,500 medical records of patients suffering from colorectal cancer were analyzed in a study of a retrospective phase in Oncologos del Occidente a Private Cancer Center from January 1995 to September 2005. 771 out of these patients correspond to gastrointestinal tumours, and 351 out of them with a diagnosis of colorectal cancer in order to identify the main prognosis factors described on the medical literature and to illustrate their behaviour regarding the survival of the patients suffering from colorectal cancer in our region. Results: Obstruction was observed on 33.7%; ulceration on 20.3%; lympho-neuro-vascular invasion on 7.5%; perforation on 2.1%; clinical state T4 on 2.3%; positive surgical margins on 1.8% and poor differentiation on 4.6%. The survival to 5 years to those patients showing perforation was 66.7% (IC 95%: 28.9-100); 79.9 on tumours T4 (IC 95% : 52.3-100); 62.5% on positive margins (IC 95%: 20-100); 42.4% on poor differentiated tumours (IC 95% :0-85), 50% out of this correspond to colon cancer and 34% to rectal cancer; 51.2% on obstruction (IC 95% :38.9-63.4); 71,9% on lympho-neuro-vascular invasion (IC 95% :52.6-91.1) and 63% on ulcerated tumour (IC 95%: 49-76.9) . Conclusions: Survival calculated in months can be correlated with number of adverse prognostic factors present (Table). [Table: see text]