Introduction: Cardiovascular complications, including left ventricular diastolic dysfunction (LVDD), are major concerns in Type 2 Diabetes Mellitus (T2DM) patients, often preceding heart failure and increasing mortality. Early detection of LVDD is essential to improving outcomes, yet current diagnostic methods are often costly and impractical for routine screening. This study aimed to evaluate the correlation between the serum triglyceride to fasting plasma glucose (TG/FPG) ratio and LVDD in T2DM patients, as a potential cost-effective biomarker for cardiovascular risk stratification. Methodology: This observational analytical study was conducted over a period of one year at a tertiary care hospital in northeast India to assess the correlation of TG/FPG ratio with LVDD in patients with T2DM. A total of 100 participants, aged 18 years or above and diagnosed with T2DM, were included. Exclusion criteria comprised Type 1 Diabetes Mellitus, pregnancy, pre-existing hypertension, cardiovascular diseases, and patients denying consent. Participants were recruited using convenient sampling, with every alternate eligible patient enrolled until the target sample size was reached. Data collection included measuring fasting plasma glucose (FPG) and postprandial blood glucose, HbA1c, fasting lipid profile, kidney function test, and urinalysis. The cardiovascular evaluation consisted of chest radiography, electrocardiogram, and echocardiography using standardized parameters to classify LVDD into grades I, II, and III, based on E/A and E/e’ ratios. Statistical analysis was performed using SPSS version 15, with Chi-square test and student’s t-tests applied for significance (p-value < 0.05), and regression analysis was used to identify associations. Ethical approval was obtained, and participant confidentiality was maintained throughout the study. Result: A cross-sectional study was conducted over one years at a tertiary hospital in northeast India, enrolling 100 participants with T2DM, excluding those with comorbidities or cardiovascular symptoms. The mean age of participants was 45.52 years, with a male-to-female ratio of 1.21:1. Diastolic dysfunction was evaluated using echocardiography, and the TG/FPG ratio was calculated for each patient. LVDD was found in 58.7% of the participants, classified into grade I (40.4%), grade II (13.5%), and grade III (4.8%). Statistical analysis revealed a significant positive correlation between the TG/FPG ratio and LVDD (p- value= 0.0001). Higher TG/FPG ratios were associated with worse diastolic function, suggesting that this ratio reflects combined metabolic disturbances contributing to myocardial dysfunction. Patients with LVDD had significantly higher lipid profiles and poorer glycemic control compared to those with normal LV function. The TG/FPG ratio, being easily obtainable from routine laboratory tests, offers a convenient tool for identifying individuals at higher risk for LVDD. Conclusion: The TG/FPG ratio may serve as a simple, accessible, and cost-effective marker for early detection of LVDD in T2DM patients. Incorporating this ratio in clinical practice could improve cardiovascular risk stratification and facilitate timely interventions, ultimately reducing the burden of cardiovascular disease in diabetic populations.