A medical tube clamp for clamping a flexible medical tube comprising: a tube receiving area which is adapted to receive the medical tube, a first clamping portion including a first clamping jaw which is movable relative to a second clamping portion including a second clamping jaw, and a closure system for safely positioning the two clamping portions in more than one snap-fit position relative to each other so that, when the closure system is unlocked, the medical tube can be inserted in and removed from the tube clamp, in an open snap-fit position the inserted medical tube cannot be removed and is not clamped and in a clamping snap-fit position the medical tube is clamped between the first clamping jaw and the second clamping jaw, with the first clamping jaw being configured to be elastically movable relative to the first clamping portion via a connecting member and/or the second clamping jaw being configured to be elastically movable relative to the second clamping portion via a connecting member. In addition, the invention relates to a volumetric pump.