Almost all cells in the human body are subjected to mechanical stresses. These forces can vary from a few Pascals (shear stress) to some Mega Pascals (on hip cartilage). It is now well known that mechanical forces have a decisive effect on cellular physiology. However, although the main biological effects of mechanical forces are well documented, the relation between mechanical stress and physiological phenomena is mainly unknown (mechanotransduction phenomenon). In this chapter, some effects of mechanical stresses on different cells (endothelial cells, vascular or muscular cells, chondrocyte, etc.) are summarized.