A multi-dose dry powder inhaler with a blister folding device is provided. The inhaler comprises a housing containing a blister strip, and a blister opening device. The blister strip comprises a plurality of individual blisters, each blister containing a dose of medicament for inhalation by a user. The blister opening device comprising a blister support element for supporting one of said blisters, and a blister folding element co-operable with the blister support element, the blister folding element and the blister support element being movable relative to each other between a first position, permitting movement of said blister into or onto the blister support element, and a second, burst, position in which the blister folding element has co-operated with the blister support element. Movement from the first position to the second position causes two spaced apart portions of said blister to each fold relative to the remainder of the blister to produce two spaced apart openings, each opening extending along the circumference of the blister bowl, beginning and terminating at points located on the fold line No piercing of the blister at any stage is required.