Ongoing low-grade chronic inflammation represents a pathogenetic background for age-related diseases. In this report, we tested the hypothesis that endogenous anti-inflammatory mechanisms may become less efficient with age, resulting in increased susceptibility to inflammatory disorders. Using previously validated ELISA assays, we evaluated urinary levels of the anti-inflammatory, pro-resolution, arachidonic acid (AA) metabolite, lipoxin (LX)A 4 and of the pro-inflammatory cysteinyl leukotrienes (cysLTs) in volunteers aged from 26 to over 100 years. (i) LXA 4 excretion was decreased in elderly people, resulting in a profound unbalance of the LXA 4 /cysLTs ratio, which may be considered an index of the endogenous anti-inflammatory potential. A significant inverse correlation was denoted between age and the LXA 4 /cysLTs ratio (ρ=−0.41, P=0.0026). We conclude that aging is associated with a switch in arachidonic acid metabolism that prevents formation of key ‘stop signals’ of the inflammatory reaction. This may contribute to promote the development of disease in elderly.