<p>Biosensor is a device which detects and combines with a biological component analysed with a physicochemical<br /> detector component. In present work we have designed a glucose biosensor using immobilised glucose oxidase enzyme<br /> on cellulose acetate produced by Aspergillus niger F– C405–2. This glucose oxidase (GO) has shown thermal stability at<br /> 600C for 120 minutes. Glucose oxidase was immobilized on pyrrol–cellulose acetate (Py–CA) film over Indium tin oxide (ITO). Platinum and silversilver<br /> chlorides are used as reference electrode and suitable for estimating blood sugar with commercial glucometer. The biosensor prepared<br /> was optimised and calibrated against standard glucose solutions of variable concentration (0.5 to 6 mg/ml) with change in electric current<br /> measured in ampere. The amount of glucose present in patient’s blood was estimated using our designed biosensor and diagnosed for diabetes.<br /> Our instrumental results were found to be correlated with that measured using commercial glucometer. No significant deviation was observed. </p>