A sensor implanted into the subcutaneous tissue has a problem in terms of long-term stability. By using a microdialysis method, glucose in the extracellular tissue fluid is recovered into the dialysate and can be easily analyzed outside the human body. The purpose of this paper is to develop a microdialysis probe with a higher recovery and a biocompatible dialysis membrane for continuous sensing of glucose in subcutaneous tissue. Long-term stability in in vivo experiments was studied by using various hollow polymer membranes such as regenerated cellulose, cellulose acetate, cellulose triacetate, polymethyl methacrylate, ethylene vinyl alcohol and surface-treated membrane such as regenerated cellulose coated with Nafion or MPC. The mass-transfer coefficient of the dialysis membrane was obtained from the recovery of glucose. The recovery of glucose with the uncovered membrane decreased clearly after three days in in vivo and in vitro experiments. The membranes coated with Nafion or MPC maintained a higher recovery than the uncoated membrane did in a sit-day Zn vivo experiment. A flexible microdialysis probe is successfully developed for continuous monitoring of glucose in subcutaneous tissues for long-term clinical application.