Deposition of age-related fluorescent pigment in tissues was initially discovered by A. Hanover in 1842 and the pigments were subsequently called lipofuscin by W. Hueck in 1912 and M. Borst in 1922. It has been known for decades that the lipofuscin is found in several aged organs such as the eyes, brain and adrenal cortex of humans and rodents. However, how these normal aging processes proceed is not known. In a preliminary study, we found that in the adrenal gland of V1a vasopressin receptor-deficient mice (V1aKO), more lipofuscin deposits were accumulated with age compared with wild-type (WT) mice. To quantitatively examine lipofuscin deposits, we have collected 60 adrenal glands from V1aKO and WT mice of both sexes at 2, 6 and 12 months of age. The sections were stained to visualize nucleus and plasma membrane and examined by using confocal microscope. We found lipofuscin fluorescent signals in the adrenal gland of both V1aKO and WT mice. However, the amount of lipofuscin in V1a-deficient adrenal gland was significantly increased compared with the adrenal gland of WT mice in both sexes at all ages. In particular, at 6 month of age, lipofuscin deposition in WT and V1aKO males occupied 3.9 and 5.6 % of entire adrenal cortex areas. Also, we found that lipofuscin accumulation started in the cytoplasm. The mechanism of an increase in this deposit formation, especially its relationship to the V1a receptor, needs to be further examined.