A fragmentation casing for a secondary projectile of a tandem warhead which includes a forwardly located active charge, a rearwardly located active charge and a fuze arranged between the charges. The secondary projectile possesses on both sides thereof a generally ovoid, thick-walled and uniformly thick nose cone with a heavy wall thickness and with an inwardly located separate fragment charge; a one-sided overhung fastening of a fuze through a collar extending between two housing parts of the secondary projectile, whereby the fuze is almost completely and; in essence, also around the periphery thereof, embedded in the explosive of the rearwardly located active charge, and with a gapless arrangement of the interconnected active charges, the casing, the prefinished fragments and the nose cones.