Background :Diabetes is one of the most prevalent disease in Indian subcontinent . periodontitis is a know as the sixth complication of diabetes mellitus . Periodontist thus are at a crucial position to examine gingival crevicular blood to screening for diabetes during there routine clinical procedures. Present study focuses on relevance of using gingival crevicular blood as a screening tool to access blood glucose level of patients. Method: 150patients with established diagnosis of chronic Periodontitis and type 2 diabetes mellitus were enrolled in the study. Blood oozing from the gingival crevices of anterior teeth following periodontal probing was collected. Similarly finger-prick blood was taken and both were was analyzed by a standard glucometer. Results:Mean ± S.D was 216. 34 ± 32.18 and 198. 83 ± 18.24 for GCB and FPB respectively was observed in patients of chronic periodontitis and type 2 diabetes mellitus. Unpaired ttest between the two values was statistically significant (p < 0.05). A Pearson correlation coefficient value of r = + 0.063 was seen comparing GCB and FPB. Conclusion:Present study supports that the gingival crevicular blood and figure prick blood do not show consistency in measuring similar blood glucose level and hence gingivalcrevicular blood show not be used as a tool to screening diabetes mellitus.