It has been well documented that interleukin (IL)-17A mainly produced by the newly identified T cell subtype Th17 cells is an important proinflammatory cytokine that plays a vital pathogenic role in the process of human inflammatory bowel diseases. Recently, new information concerning the biological activities of IL-17A relating to the development of colorectal cancer (CRC) has also been reported. The present mini-review focuses on recent observations concerning the role of IL-17A in the development of CRCs, and it discusses the clinical significance of IL-17A as a biomarker and potential therapeutic target.