Updated project metadata. The circadian clock is an endogenous oscillator that drives daily rhythms in physiology, behavior and gene expression. The underlying mechanisms of circadian timekeeping are cell-autonomous and involve interconnecting transcription-translation feedback loops. The hippocampus plays an important role in spatial memory and the conversion of short-term to long-term memory. Several studies have reported the presence of a peripheral oscillator in the hippocampus, and have highlighted the importance of circadian regulation in memory formation. In this study we performed global quantitative proteome and phosphoproteome analyses of the murine hippocampus across the circadian cycle, applying spiked-in labeled reference and high accuracy mass spectrometry.