ABSTRACT Background: Valvular heart disease (VHD) often presents with subclinical left ventricular (LV) dysfunction that may not be detected by traditional echocardiographic parameters. This study explores the utility of global longitudinal strain (GLS) as an early marker of LV dysfunction in patients with VHD. Material and Methods: A descriptive and cross-sectional study was conducted at Dr. D. Y. Patil Medical College, Pune, from July 2022 to July 2024, involving 100 patients diagnosed with VHD and scheduled for two-dimensional (2D) echocardiography. Clinical data, including demographic characteristics, medical history, and symptoms, were recorded. Participants underwent echocardiographic evaluation using 2D and speckle-tracking echocardiography to assess GLS, LV volumes, ejection fraction, and other myocardial deformation parameters using Vivid™ E95 Ultra Edition ECHO machine. The analysis was done by the single operator to avoid operated-related bias and discrepancy. Statistical analysis was performed using the IBM software SPSS version 26.0. Results: The majority of participants with GLS ≤17 were aged >60 years and had severe symptoms, including chest pain, dizziness, and NYHA class IV dyspnea. GLS ≤17 was strongly associated with higher NT-proBNP levels, larger left atrial (LA) size, and significant valvular abnormalities, particularly aortic stenosis, aortic regurgitation, and mitral regurgitation. Notably, GLS ≤17 showed poor correlation with mitral stenosis (MS). Lower GLS values correlated with worse echocardiographic findings, reflecting myocardial dysfunction and structural changes. Conclusion: GLS serves as a sensitive marker for the early detection of subclinical LV dysfunction in VHD, particularly in conditions involving regurgitation or stenosis. The association of GLS ≤17 with elevated NT-proBNP levels and increased LA size underscores its potential in identifying early myocardial stress. However, its limited applicability in MS highlights the need for further research in specific valvular pathologies. This study supports GLS as a valuable tool in the early diagnosis and management of subclinical cardiac dysfunction in VHD.