Strips containers are formed using two continuous webs in thermoformable and heat-sealable material facing each other. The webs are indexed along a feed line through different operating stations that transform the webs into a continuous strip of containers, each one of which is provided with a mouth. The containers are arranged according to two parallel rows that are opposed to a longitudinal median zone. The mouths of the containers of the upper row are arranged on the upper longitudinal edge of the strip and face upwards, whilst the mouths of the containers of the lower row are arranged on the lower longitudinal edge and face downwards. The method enables productivity to be increased and waste to be reduced.