A bare, bent and tapered multimode optical fibre (BTBMOF) has been used as a sensor probe to find the refractive index of glucose solution. The sensor system consists of a diode Laser source, the sensor probe and a Light dependent resistor (LDR) as detector. The optical fibre sensor has been used for measuring the concentration of glucose solution by using the change in refractive index (RI) of the glucose solution due to change in concentration. Keywords:Optical fibre sensor, Glucose, Refractive index