Abstract: The invention relates to a process for drying timber in which the timber is fed gradually through a drying tunnel while at the same time being permeated by a drying air with a temperature below 80.degree. C. transported primarily in the longitudinal direction of the tunnel. Said drying tunnel is divided into two separate sections with said drying air divided into two circulating substreams, of which one flows through the first section of the tunnel in the direction of motion of the timber and the other through the second section of the tunnel contrary to the direction of motion of the timber, after which said substreams are conditioned and returned to their section.