Genome editing techniques are considered to be one of the most challenging yet efficient tools for assisting therapeutic approaches. Several studies have focused on the development of novel methods to improve the efficiency of gene editing, as well as minimise their off‑target effects. Clustered regularly interspaced short palindromic repeats (CRISPR)‑associated protein (Cas9) is a tool that has revolutionised genome editing technologies. New applications of CRISPR/Cas9 in a broad range of diseases have demonstrated its efficiency and have been used in ex vivo models of somatic and pluripotent stem cells, as well as in in vivo animal models, and may eventually be used to correct defective genes. The focus of the present review was the recent applications of CRISPR/Cas9 and its contribution to the treatment of challenging human diseases, such as various types of cancer, neurodegenerative diseases and a broad spectrum of other disorders. CRISPR technology is a novel method for disease treatment, enhancing the effectiveness of drugs and improving the development of personalised medicine.