[Structure: see text] Peroxyl radicals formed from the addition of oxygen to carbon radicals of N-acetyl glycine, serine, and diglycine are directly observed at room temperature via time-resolved EPR spectroscopy. Isotopic labeling confirms the identity of the N-acetyl glycine and diglycine peroxyl analogues. The peroxyl radicals show unusually strong chemically induced electron spin polarization which is discussed in terms of the radical pair mechanism and spin polarization transfer processes.