The CRISPR (clustered regularly interspaced short palindromic repeat)-Cas9 (CRISPR-associated nuclease 9) method has been dramatically changing the field of genome engineering. It is a rapid, highly efficient and versatile tool for precise modification of genome that uses a guide RNA (gRNA) to target Cas9 to a specific sequence. This novel RNA-guided genome-editing technique has become a revolutionary tool in biomedical science and has many innovative applications in different fields. In this review, we briefly introduce the Cas9-mediated genome-editing tool, summarize the recent advances in CRISPR/Cas9 technology to engineer the genomes of a wide variety of organisms, and discuss their applications to treatment of fungal and viral disease. We also discuss advantageous of CRISPR/Cas9 technology to drug design, creation of animal model, and to food, agricultural and energy sciences. Adoption of the CRISPR/Cas9 technology in biomedical and biotechnological researches would create innovative applications of it not only for breeding of strains exhibiting desired traits for specific industrial and medical applications, but also for investigation of genome function.