Protein is the essential part of human body, in hemodialysis process sometimes it seeps out through dialysis membrane, which enters in waste dialysate material. This book focuses on a protein sensor which can be placed in dialysis machine to monitor the protein leakage in dialysate material. The sensor consists of electrodes system and micropump. The micropump carries the dialysate material towards the electrodes and electrodes sense the presence of protein in dialysate material. The protein sensor is composed of three sensing electrodes, including a working electrode, a counter electrode and a reference electrode. The principle of the proposed sensor is the change in the electric current between the working and the reference electrodes. When protein is absorbed on to the working electrode it reduces the conducting area, as a result resistance increases and current decreases between working electrode and reference electrode. This change of current is used for the measurement of the concentration of protein in the waste dialysate material. The purposed sensor can also be use for urinary protein.