Gingival crevicular fluid blood (GCFB), during periodontal probing is useful to assess blood sugar levels using a glucometer. Hence, blood glucose levels in chronic periodontitis with and without diabetes were measured using gingival crevicular fluid and compared to finger stick blood glucose levels (FSBG). A total of 48 patients (24 diabetics and 24 non-diabetics) with chronic periodontitis who matched the inclusion criteria were divided into two groups, Group I and Group II, respectively. The entire patient’s plaque and Russel's periodontal indices were recorded and a glucometer was used to measure random blood glucose from the gingival crevicular fluid and finger pricks. A positive association between the blood glucose level measured by a fingerstick and the gingival crevicular fluid is observed. Thus, GCFB can be used as a reliable chairside diagnostic technique for diagnosis diabetes in a dental setting.