Colorectal cancer (CRC), the third most prevalent cancer worldwide, imposes a significant economic and humanistic burden on patients and society. One study conservatively estimated the annual expenditures for colorectal cancer to be approximately dollars US 5.3 billion in 2000, including both direct and indirect costs. However, other investigators estimated inpatient costs alone incurred in the US in 1994 to be around dollars US 5.14 billion. Therefore, the economic burden of colorectal cancer in the US could be projected to be somewhere in the range of dollars US 5.5-6.5 billion by considering that inpatient costs approximate 80% of total direct costs. No worldwide data have been published, but assuming that the US represents 25-40% of total expenditures in oncology, as seen for breast and lung cancers, a rough estimate for colorectal cancer would be in the range of dollars US 14-22 billion. Screening helps increase patient survival by diagnosing colorectal cancer early. The ideal method among the four tests most used (faecal occult blood test, flexible sigmoidoscopy, colonoscopy and double contrast barium enema) has not been identified. Economic studies of colorectal cancer screening are complex because of the many variables involved, as well as the fact that the outcomes must be followed for many years, and the lack of consensus on screening guidelines. Intuitively, modelling colorectal cancer is one way to overcome these hurdles; published modelling studies predict colorectal cancer screening programs to be within the threshold of dollars US 40000 per life-year saved. The faecal occult blood test appears to be the only clearly effective test, both from a clinical and an economic viewpoint. Important limitations are the invasiveness and inconvenience of the screening procedures, except faecal occult blood test. Patients' comfort and satisfaction are essential in improving compliance with screening recommendations, which appears to be low even in the US (35% of the general population aged over 40 years and 60% of the high-risk population), the country with the highest awareness and compliance in the world. Since colorectal cancer is generally a disease of the elderly, its economic burden is expected to grow in the near future, mainly due to population aging. Potential avenues to pursue in order to contain or reduce the economic burden of colorectal cancer would be the design and implementation of efficient screening programmes, the improvement of patient awareness and compliance with screening guidelines, the development of appropriate prevention programs (i.e. primary and secondary), and earlier diagnosis.