A drive assembly (2) for a pen-type injector, comprising: a guiding means (40) having a first (42) and a second end (41), a drive means (20), an elongate member (30) coupled to the guiding means (40) and adapted to be driven by the drive means (20) for displacing the guiding means (40) with respect to the drive means (20), a piston member (60) displaceably disposed at the first end (42) of the guiding means (40) and an adjusting member (62) displaceably disposed at the second end (41) of the guiding means (40), wherein the drive means (20) is fixedly located with respect to the adjusting member (62), and wherein the piston member (60) and the adjusting member (62) are coupled such that the sum of the distance between the piston member (60) and the guiding means (40) and the distance between the adjusting means (62) and the guiding means (40) remains constant, and a pen-type injector with such a drive assembly.
