To provide a novel crystal of 5-aminolevulinic acidphosphate having a high thermal stability, a high meltingpoint, and an excellent moisture absorption resistance aswell as a process for producing the same.A crystal of 5-aminolevulinic acid phosphate, whichshows characteristic peaks at 7.9° ~0.2°, 15.8°~0.2°,18.9° ~0.2°, 20.7° ~0.2°, 21.1°~0.2°, 21.4° ~0.2°, 22.9°~0.2°, 33.1° ~0.2°, and 34.8 ~0.2° as diffractionangles 20in a powder X-ray diffraction, and a process forproducing the same.