CRISPR/Cas9 (clustered regularly interspaced short palindromic repeat/CRISPR-associated Cas9)-based gene editing is a robust tool for functional genomics research and breeding programs in various crops. In soybean (Glycine max), a number of laboratories have obtained mutants by the CRISPR/Cas9 system; however, there has not yet been a detailed method for the CRISPR/Cas9-based gene editing in soybean. Here, we describe the procedures for constructing the CRISPR/Cas9 plasmid suitable for soybean gene editing and the modified protocols for Agrobacterium-mediated soybean transformation and regeneration from cotyledonary node explants containing the Cas9/sgRNA (single-guide RNA) transgenes.