Packaging for transporting radioactive material (1) comprising a radiation protection structure (4) comprising a shielding portion (5) defining a cavity (2) to house the radioactive material and a portion (7) having the effect of distancing the radioactive material from the outside of the packaging. The distancing-effect portion (7) directly encloses the shielding portion (5). The protection structure (4) has a thickness e associated with a segment (S) connecting a point (B) on the outer surface of the packaging to the center of gravity (G) of the cavity (2). It satisfies for any point (B): e=e1+e2 and 0.05