Mechanobiology is now a vigorous branch of biomechanics and biorheology which is mainly concerned with the study of the influence of mechanical forces on cells and tissues and their clinical or therapeutical applications. As we are now at the age of proteomics and genomics and of cell micromechanical approaches, using methods like laser tweezers or confocal microscopy, mechanobiology brings new challenges. With these new researches, mechanobiology is the promise of new diagnostic and therapeutic approaches. The most recent work shows that the incidence of mechanical forces is specific to the system under scrutiny and that stresses are implicated in tissue physiology (for example by the production of the extracellular matrix), secretions (i.e. production of NO and prostaglandins by endothelial cells), or for the induction of specific functions via intercellular communication; hence the interest from pharmacology in studies on new molecules. Moreover, these new findings have led to the development of tissue engineering, which is the concept of substitute tissue developed in vitro, from bioresorbable or non-bioresorbable scaffolds and from cells harvested in a physiologic mechanical environment such as from cartilage, bone and vessels. At the same time, the problem of cell grafting in tissue repair and especially the use of stem cells have led to new therapeutic fields.