Cellular senescence is a biological process associated with aging and longevity. Successful aging is believed to be related to the ability to cope with different environmental stresses. The objective of this study was to investigate if cellular senescence is associated with platelet membrane modifications on subjects of different age, in particular on monozygotic twins and if these changes might be affected by both genetic components and environmental factors. The work was performed on 81 monozygotic twin pairs of different age. Platelet membranes from centenarian twins showed: decreased both basal lipid peroxide levels and membrane fluidity compared with elderly subjects; Na(+)/K(+)-ATPase activity and SA content are similar to those evaluated in young group, suggesting one of their important roles in the successful aging. We concluded that platelet membranes from centenarians show deeper structural and functional modifications than in elderly subjects and that these changes might play a protective role against oxidative damage. No statistical difference in biochemical parameters was observed between two sibpairs in each twin pair highlighting that environmental factors (diet, life-style) affect age-related platelet membrane changes less than their common genetic component. Thus genetic factors might play an important role in the mechanisms at the basis of successful aging.