Effective lymph flow is crucial for fluid and macromolecules homeostasis, fat absorption, and immunity. Studies of the last decade significantly advanced the understanding of the basic mechanisms controlling lymph flow, and therefore all processes indicated above. The major units of lymphatic vessels, lymphangions, pump lymph in self-regulatory mode through constant adjustment of their contractions to the complicated combinations of lymph pressures and flows. Lymphatic vessels provide the energy of contractions of their muscle cells to support an effective unidirectional lymph flow. Muscle cells are able to adjust their contractile characteristics depending on variable levels of wall stretch, which determines by preload and afterload of lymphangions. Lymphatic endothelial cell are tightly involved into functional adaptation of the contracting lymphangions through wall shear-stress dependent mechanisms. At moderate levels of the wall shear stress the lymphatic endothelium generates phasic spikes of NO release, supporting the most energy-sufficient mode of the lymphatic pumping. At high levels of steady lymph flow, which reflect higher levels of lymph formation, lymphatic relaxation diminishes resistance to passive lymph flow. Regional variability of the regulatory mechanisms of lymph flow relates to the existence of the additional, not completely discovered regulatory pathways involved into stretch- and flow-dependent modulation of lymphatic contractility. Aging alters all of these functions, however even status of contractility and flow in aged lymph vessels is not well characterized. The role of the oxidative stress as risk factor for aging of lymph vessels are unknown. 9-mo and 24-mo old Fischer-344 rats were used. Specimens of isolated mesenteric vessels (MLV) were dissected from animal underwent anesthesia by Sodium Pentobarbital 50 mg/kg weight I.P., at the end of dissections animals were humanely euthanized by injecting Sodium Pentobarbital 100 mg/kg body weight IP. Diameters/pump indices of isolated/pressurized segments of the mesenteric lymph vessels were determined. High-speed cell microscopic video monitoring was used to calculate lymphatic diameters, contraction frequency, flow velocity, and wall shear stress in vivo. Application of the non-selective nitric oxide synthase inhibitor – L-NAME in 100 μM was implemented. Protein expression of three isoforms of superoxide dismutase (SOD) and 3-nitrotyrosine has been determined, their immunohistochemical labeling has been performed. The SOD activity and levels of lipid peroxidation were evaluated. Live vessel fluorescent imaging with dihydroethedine for whole MLV, and with Mitotracker Red – for mitochondria, allowed to compare the levels of superoxide anions in adult and aged MLV. We found weakening of the lymphatic pump in isolated aged MLV including diminished tone, contraction amplitude, and frequency with corresponding decrease in their minute productivity. Application of L-NAME is able to enhance contractility of aged MLV. Data demonstrate diminished ability of the aged MLV to resist to oxidative stress: decreased SOD activity referred to diminished expression of its Cu/Zn isoform. High levels of superoxide anions and increased levels of lipid peroxidation confirmed in aged MLV. Cumulatively, our findings support the idea that in aged tissues surrounding the aged MLV, the additional source of some yet unlinked lymphatic contraction-stimulatory metabolites is counterbalanced or blocked by NO release. The aging-associated increases in oxidative stress and oxidative damage is indeed present in the walls of MLV and may contribute to the aging-associated lymphatic pump dysfunction.