Podocytes play an important role in glomerular function. Together with endothelial cells of the glomerular capillary loop and the glomerular basement membrane they form a filtration barrier. Podocytes cooperate with mesangial cells to support the structure and function of the glomerulus. With regard to its structure, the podocyte can be divided into three structural and functional segments: cell body, major processes, and foot processes, the latter playing a crucial role in the pathogenesis of proteinuria. Podocytes are end-differentiated cells with specific phenotypic features associated with their function. The compensatory ability of these cells is limited to hypertrophy. Under normal conditions a podocyte cannot restart the cell cycle. Attention has recently been drawn to the importance of slit diaphragms in the pathogenesis of proteinuria. Structural damage to each of the slit diaphragm proteins as well as disturbances in their mutual interactions can result in insufficiency of the filtration barrier.