Diabetes and periodontal health status have long been considered to be biologically linked. It is essential for a dental surgeon or a periodontist to detect blood glucose level for patients whose signs and symptoms are suggestive of diabetes. Self monitoring devices provide a simple method for rapid monitoring of the glucose level in blood. The present study was designed to check the validity of glucometer as a chairside diagnostic device in chronic periodontitis patients with and without diabetes. The study included 45 patients divided into three groups (15 chronic periodontitis patients with diabetes mellitus, 15 chronic periodontitis patients without diabetes mellitus and 15 healthy patients). Samples were taken from gingival crevicular, gingival capillary, finger prick blood and values were compared with standardized venous blood sample results. The results of study show a strong correlation between blood sugar values of gingival crevicular blood with laboratory venous blood sugar than other parameters.