The invention relates to a microdialysis catheter comprising a multilumen tube (10) and a membrane (11), said tube exhibiting at least two longitudinally arranged inner channels (13,14), said channels extending from a proximal (20) end of the tube to the distal end (21) of the tube, whereat through-holes (12,15) are provided, one from each of said at least two channels to the outside of said tube, said channels (13,14) blocked for passage of liquid distally of the respective through-holes, a tubular membrane (11) arranged circumferentially around the tube (10) such as to cover the at least two through -holes (12,15), said membrane is sealingly fastened (22) to the tube thereby forming a dialysis chamber (18) between the tube and the membrane.