Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9 is a genome editing tool that helps scientists modify the DNA of living organisms selectively and precisely. The discovery of this system has led to changes in the approaches to gene therapy. In this article, I delve into the role of CRISPR-Cas9 in the development of treatment using gene therapy and the drawbacks of this system. Also, I discuss the role of medical writers in the dissemination of information and research on CRISPR-Cas9 and gene therapy. Medical Writing. 2023;32(4):46–49. https://doi.org/10.56012/lzwz4471