Colorectal cancer (CRC) is the fourth most common cancer in the UK and the incidence has increased over recent decades. Although only 1.5% of cases are diagnosed in those aged under 40 years, it remains an important condition to be aware of in the military population. Patients who are genetically predisposed can have a lifetime risk of 80-100% of developing CRC and are likely to develop symptoms during their service. 20% of patients will present with metastatic disease. While surgical and oncological treatments have improved outcomes, early diagnosis of CRC is essential to reducing mortality. This paper provides an overview of the aetiology, investigations and treatment options for CRC. Explanation of primary surgical options and the principles of adjuvant therapies are included to aid informed discussions with patients.