In utero electroporation has been extensively used to study a variety of developmental questions in the developing brain. This protocol aims to provide the basic knowledge for a beginner to get familiar with the technique. Basically, by electroporating a DNA construct into a subpopulation of progenitor cells in the ventricular zone of embryonic brain, the progenitor cells carrying the DNA will undergo neurogenesis, migration, and final differentiation to become mature neurons positioned in distinct cortical layers according to their birth date. In addition, by controlling the direction of electroporation, a specific cortical area can be targeted. Thus, in utero electroporation allows gene modification in a specific cortical layer in a specific cortical area.