Glutaric acid (Pentanedioic Acid) is a linear dicarboxylic acid. It has been prepared by oxidizing cyclopentane, cyclopentanol and cyclopentanone. Glutaric acid is formed as an intermediate during the catabolism of lysine in mammals. Electron spin resonance spectra of radical (CO2H)CH2CH2CH(CO2H formed in glutaric acid crystal after γ-irradiation is reported to remains trapped in it. Polymorphism of Glycine-glutaric acid co-crystals has been studied by single crystal X-ray diffraction and Raman spectroscopy. Glutaric acid is a pentanedioic acid. On exposure to X-rays, glutaric acid crystals generate two stable free radicals. These free radicals have been investigated by electron nuclear double resonance (ENDOR) technique. Presence of glutaric acid in urine and plasma is an indicator of type I glutaric aciduria (GA-I).