Aim: Periodontal disease is associated with gingival bleeding. Thus, the present study was aimed towards evaluating, whether the blood oozing during routine periodontal examination can be used for evaluating blood glucose levels. Materials and methods: A total of 100 patients reporting to Department of Oral Medicine and Radiology, within the age group of 25–55 years were enrolled. In fasting condition, gingival crevicular blood (GCB), finger-stick blood (FSB) was measured using a glucometer and venous blood (VB) glucose values were measured in the laboratory with glucose oxidase method. All the parameters thus recorded were then subjected to statistical analysis. Results: When compared, the GCB glucose values, VB glucose values and the FSB glucose values measured with glucometer in the diabetic and nondiabetic group were found to be highly statistically significant (p = 0.000). Conclusion: Gingival crevicular blood collected during diagnostic periodontal examination can provide a valid and acceptable source for measuring blood glucose levels using a glucometer. In addition, the technique described is quick, safe, easy to perform and more acceptable to the patients. Clinical significance: Dental surgeon can play an active role in screening of patients for glucose levels during routine periodontal examination and help to increase the frequency of diabetes screening in dental offices especially in undiagnosed diabetic cases which can be referred to the physician for appropriate management of the condition.