An injector for injecting fluid from a syringe mounted thereon includes a housing, a drive member at least partially disposed within the housing and operable to engage a plunger of the syringe, and a syringe retaining mechanism associated with the housing. The syringe retaining mechanism is adapted to releasably engage the syringe regardless of the orientation of the syringe with respect to the injector. Further, the retaining mechanism is preferably movable upon rotation of the syringe between a relaxed state, where the syringe is engaged by the retaining mechanism, and a tensioned state, where the syringe is released from the retaining mechanism.