A medicament container retaining mechanism for a medicament delivery device includes at least one flexible retaining member arranged to a first housing part of the medicament delivery device. The first housing part is configured to receive a generally tubular medicament container. The at least one flexible retaining member is configured to interact with a rim of the received medicament container, and the at least one flexible retaining member is configured to exert a mainly longitudinally directed clamping force on the rim of the medicament container to prevent movement in the generally longitudinal direction of the medicament container in the housing part.