An autoinjector includes a rear body assembly (10) connected to a front body assembly, wherein the rear body assembly (10) contains a drive mechanism (60 . . . ) and the front body assembly contains a syringe (13) or cartridge with a needle at its forward end, the front body assembly including a viewing window (22) through which at least part of the contents of the syringe (13) or cartridge are visible, a removable cap (14) fitted to the forward end of the front body assembly the rear body assembly and the removable cap having respective aligned cut-away regions together defining a frame for the viewing window. Also disclosed is a modular scheme which uses a common platform for the provision of a range of autoinjectors of different fill volumes, with only the length of the plunger (60), and the axial extent of the cut out varying between different versions.
