Several hematologic diseases with genetic defects, like sickle cell disease and β-thalassemia can be treated with allogeneic hematopoietic stem cell transplantation (HSCT) from healthy donors. However, suitable tissue-matched donors are often unavailable, and HSCT involves risks such as graft-versus-host disease and potential disease relapse. Due to the genetic heterogeneity of blood disorders and the complexity of the hematopoietic system, identifying effective genes for managing and treating both benign and malignant conditions remains a significant challenge. The genome editing field is rapidly expanding and is essential for identifying genetic factors in pathological processes. These developments highlight the importance of using ex vivo gene therapy approaches for autologous hematopoietic stem cells. Also, gene editing technologies are gaining significant interest in engineered cell therapies for hematological malignancies . Today, various programmable nucleases are available for genome editing, with the clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) system standing out due to its high efficiency, low cytotoxicity, cost-effectiveness, and precision. This system can serve as a genomic modification tool for treating blood disorders, including hereditary diseases and immunotherapy for cancer using chimeric antigen receptor T cells (CAR-T cells). Advancements in CRISPR-Cas9 are expected to significantly impact medical research and clinical applications. However, challenges such as off-target effects and immunogenicity must be addressed. This review summarizes the mechanism and delivery strategies of CRISPR-Cas9, discusses its applications in treating inherited blood disorders such as sickle cell disease, β-thalassemia, and fanconi anemia, as well as hematological malignancies, and highlights the associated challenges.