A cartridge holder for a drug delivery device. The cartridge holder comprises a proximal portion for receiving a cartridge filled with a medicinal fluid to be dispensed by the drug delivery device, and a distal portion comprising a mount for a piercing assembly. The piercing assembly is adapted to provide a fluid-transferring connection with the inner volume of the cartridge by way of a piercing element pointing in distal direction with a pointed free end section. Retaining means adapted to substantially prevent the cartridge from displacing in proximal direction with respect to the proximal portion distal portion.