The pathophysiology of several kinds of congenital stationary night blindness (CSNB) has been clarified in the last years, following the analysis of the visual function and molecular genetics. This chapter reviews recent knowledge of four kinds of CSNB: complete CSNB, incomplete CSNB, fundus albipunctatus, and Oguchi's disease. All these types of CSNB show the negative waveform in the dark-adapted single bright-flash (mixed rod-cone) electroretinogram (ERG) after 20–30 minutes of dark adaptation (see below). The identification of the mutant genes causing forms of CSNB in combination with the electrophysiological analysis refines the classification of these diseases and enhances our understanding of the underlying pathophysiology.