A dose counter mechanism is suitable for use with a medicament delivery device. The dose counter mechanism comprises a rollable tape (20) provided with indicia (22), a tape housing (10) and a tape collector spool (40). The tape housing comprises a tape dispenser housing (14) within which, in use, a roll (24) of the tape is inserted and a tape collector spool housing (16) within which, in use, the tape collector spool is mounted. The tape dispenser housing and the tape collector spool housing are connected by a tape display area (15).