The presence, distribution, and histological features of lipofuscin granules were investigated in brains of the dendrobranchiate decapods Marsupenaeus japonicus Bate, 1888, Melicertus kerathurus (Forskål, 1775), Parapenaeus longirostris (Lucas, 1846) (family Penaeidae), and Aristeus antennatus (Risso, 1816) (family Aristeidae). Autofluorescent lipofuscin granules were prominent in wax sections of olfactory-lobe cell masses (OLCMs) of all the species but P. longirostris, in which the pigment granules could be distinctly identified only in histological sections of samples embedded in resin. Although quantification was not carried out in this study, the amount of lipofuscin was visibly higher in larger and older individuals. Lipofuscin granules are secondary lysosomes of heterogeneous content that derive from autophagic vacuoles. In samples treated for electron microscopy, cytoplasmic inclusions assumed to be lipofuscin granules stained positive with Sudan Black B, whereas all brains processed for light microscopy (embedded in either paraffin wax or resin) were Sudan Black B negative. No acid phosphatase activity was evidenced cytochemically in lipofuscin granules of M. japonicus OLCMs. The variable histochemical properties of lipofuscins suggest that, as has been shown previously for other decapods, the most accurate method for localization and quantification of the age-pigment in dendrobranchiates is the one based on autofluorescence. This technique is thought to be valuable in assessment of the age structure of shrimp natural stocks.