Background: Gestational Diabetes Mellitus (GDM) is defined as any glucose intolerance that first occurs or is first diagnosed in pregnancy. GDM is long known to be associated with neonatal and maternal morbidity. Early screening and better diagnostic tools can help decrease chances of GDM. One of the most accessible and inexpensive inflammatory markers is platelet indices. Various studies show that indices like platelet count, mean platelet volume, plateletcrit, platelet to lymphocyte ratio have association with GDM occurrence but there is lack of such studies among the Indian population. This study aimed to investigate the association between mean platelet volume and the risk of GDM occurrence using maternal CBC sampling in the second trimester of pregnancy. Materials and Methods: This cross-sectional study included 2 groups of 66 pregnant women with and without GDM. The women in each group were compared after the routine screening for GDM and CBC test at 24–28 weeks’ gestation after being matched according to the inclusion criteria. All the statistical analysis were done using Epi info version 7.2.1.0 statistical software. Results: The two groups were compared with respect to various sociodemographic factors I. e., age, parity, religion, literacy status where the resulting difference was statistically significant in case of their socioeconomic status where majority (50%) of GDM pregnancies belonged to Lower class compared to 51.1% of healthy pregnancies from lower middle class. The difference in values of mean platelet volume among the two groups was found to be statistically significant (p<0.001). In the ROC, the area under the curve was 0.86 and with critical cut off value as 12.45fL, the sensitivity and specificity were 71.2% and 87.9% respectively. Conclusion: Given the inflammatory nature of the disease, GDM and associated high levels of maternal and fetal morbidities, an adjunct to present screening techniques is needed. Our study infers that mean platelet volume is a highly specific indicator of GDM. These values can further be studied in first trimester of pregnancy which may further be helpful in earlier diagnosis of GDM.