Colorectal cancer (CRC) is one of the most frequent neoplasia in developed countries and the second leading cause of cancer death in Spain. It develops through the accumulation of genetic and epigenetic alterations in the normal mucosa, producing advanced adenomas and invasive cancers. This multistep process makes CRC highly traceable, making it a good candidate for the implementation of preventive measures such as screening programs. Although there are different strategies, none of them meet all the criteria for CRC screening purposes. In this context, many molecular alterations involved in CRC carcinogenesis could contribute to the generation of new non-invasive methods with a high sensitivity and specificity. In this review, some of the most promising diagnostic non-invasive biomarkers for CRC will be briefly discussed.