Discovery of (pro)renin receptor elucidated that prorenin is not only an inactive precursor of renin but also an endocrine hormone. The binding of prorenin to the (pro) renin receptor triggers two major pathways: the angiotensin II-dependent pathway as a result of nonproteolytic activation of prorenin, and the angiotensin II-independent, (pro)renin-receptor-dependent intracellular pathways. These two pathways of (pro)renin receptor significantly contribute to the development and progression of end organ damage in diabetes and hypertension. However, since renin is still active in the absence of the (pro)renin receptor, the contribution of (pro)renin receptor to the pathogenesis is reduced under conditions with high renin levels. Thus, assessment of the ratio of renin to prorenin is needed to evaluate the significance of (pro)renin receptor.