The increasing incidence of colorectal cancer force to find new and enhance old methods of diagnostic methods that could allow the pre-magnant or early cancer lesions diagnosing. Those could be more effectively and with less invasive surgical and endoscopic methods cured. The proposed method in prophylaxis is colonoscopy that allow the lesion detection as well as apply curative method what is better for patient and decrease cost of procedure. Diagnostic efficacy is dependant on the experience of the person performing the procedure. Only in some cases applying methods as inking or magnifying increase diagnostic yield. Early lesion detection and treatment of colorectal adenomas that could be protruding, flat or concave lead to significant decrease of colorectal cancer incidence. Implementing the wider array of indications and mucosectomy to clinical practice improve treatment efficacy but require proper preparation and experience as well as qualification for the procedure. Despite the development of new diagnostic methods basis the proper evaluation of mucosal layer during endoscopy and histopatological assessmnet of found lesions. Colonoscopy is also widely accepted method of colorectal cancer surveillance after endoscopic or surgical procedures in colorectal treatment.