An injection device comprises a multi-use drive assembly 10 and a single use disposable syringe assembly 12 releasably connected thereto. The syringe assembly comprises a syringe 18 and a shield 26 mounted for telescopic movement. The drive assembly 10 is operable to extend the syringe 18 relative to the shield 26 and then to express a dose. Continued forward drive movement extends the shield 26 to re-cover the syringe needle 22 and then ejects the spent syringe assembly 12 in a safe (shrouded) condition. Refer to Figs 1, 2.