It has been well established that the rising phase of the scotopic electroretinogram (ERG) a-wave largely represents the massed electrical response of the rod photoreceptors.^{9,11,17,19,20,36,45} This has motivated wide use of the ERG to study fundamental and clinically relevant aspects of rod function in the living eye. However, a severe constraint associated with conventional (i.e., single-flash) ERG recording is that intrusion by the b-wave and other postreceptor ERG components begins to mask the a-wave shortly after test flash presentation and thus obscures all but the initial portion of the photoreceptor flash response. The constraint is especially pronounced in the case of rods in the mammalian eye. That is, intrusion by the b-wave in the mammalian ERG becomes substantial at ∼25ms or less after test flash presentation, while photocurrent data from mammalian rods in vitro indicate a flash response duration of at least several hundred milliseconds.^2,26,33 Recently, however, we and others have developed a paired-flash ERG technique that allows approximate determination of the rod response's full time course.^{3,14,16,29,37,39,41} The aim of this chapter is to describe the measurement of rod phototransduction and adaptation properties using the paired-flash ERG method. The work to be highlighted is drawn from recent studies conducted on human subjects and on wild-type (C57BL/6J) mice.