The magnetic nano-materials, Co/graphitic carbon- (GC-) shell nanocrystals, were made via chemicalvapour deposition (CVD) method, and their biodistribution and excretion in mice were studied by using postintravenously (i.v.) injecting with 60Co–Co/GC nanocrystals. The results showed that about 5% of Co was embedded into graphitic carbon to form multilayer Co/GC nanocrystals and the size of the particle was ~20 nm, the thickness of the nanocrystal cover layer was ~4 nm, and the core size of Co was ~14 nm. Most of the nanocrystals were accumulated in lung, liver, and spleen after 6, 12, 18, and 24 h after i.v. with 60Co–Co/GC nanocrystals. The nanoparticles were cleared rapidly from blood and closed to lower level in 10 min after injection. The 60Co–Co/GC nanocrystals were eliminated slowly from body in 24 h after injection, ~6.09% of 60Co–Co/GC nanocrystals were excreted by urine, ~1.85% by feces in 24 h, and the total excretion was less than 10%.