The transport and accumulation of orally administered functional food-derived peptides in the brain was not fully explored. Thus, in the present study, we aimed to provide critical evidence regarding brain accumulation of a memory-improving soy dipeptide, Tyr-Pro, following oral administration. Stable isotope-labeled Tyr-Pro (Tyr-[^C_5,^N]Pro) was orally administered to male ICR mice at 10 or 100 (mg)/(kg). Surprisingly, the intact labeled Tyr-Pro exhibited maximal plasma and brain levels 15 min after administration (plasma: area under the curve [AUC_], 1331 ± 267 pmol·min/mL-plasma; brain: AUC_ of 0.34 ± 0.11 pmol·min/mg-dry brain, at 10 (mg)/(kg)). In addition, we detected labeled Tyr-Pro in the brain parenchyma, indicating a validated blood–brain-barrier (BBB) transportability. Moreover, we confirmed the preferable accumulation of Tyr-Pro in the hypothalamus, hippocampus, and cortex with > 0.02 pmol/mg-tissue. In conclusion, we provided the first evidence that orally administered Tyr-Pro at 10 (mg)/(kg) directly entered the blood circulation with an absorption ratio of 0.15%, of which 2.5% of Tyr-Pro was transported from the plasma to the mouse brain parenchyma.