Although impairments of the circadian system are believed to be involved in accelerated aging, little is known about how the circadian clock in different tissues is altered across the lifespan. In Drosophila, PER expression remains robust in central pacemaker neurons (Luo et al., 2012) but is significantly reduced in retinal photoreceptors (Luo et al., 2012; Rakshit et al., 2012). While glia have many important roles in maintaining nervous system homeostasis, it is not known which glial subtypes express the core clock protein PER and whether PER levels remain similar across lifespan or decline with age. To address these questions, we took advantage of the fact that glial subtypes of Drosophila have unique expression patterns and can be labeled separately by GFP via cell-type specific drivers. We performed 2-timepoint immunocytochemical experiments to identify Drosophila glia subtypes that express PER protein and determined that the PER level in these cells is reduced in old fly brains compared to young.