The International Classification of Diseases (ICD), developed by the World Health Organization (WHO), is a globally recognized system for classifying diseases, injuries, and health-related conditions. It provides a standardized framework for collecting, analyzing, and comparing health data across populations and healthcare systems worldwide. This article explores how the ICD enables international comparisons of health indicators, including mortality, morbidity, and composite measures such as Disability-Adjusted Life Years (DALYs) and Quality-Adjusted Life Years (QALYs). By ensuring uniform disease classification and coding, the ICD supports global epidemiological surveillance, healthcare resource allocation, and policy-making. However, challenges such as variations in healthcare systems, coding inconsistencies, and data collection limitations can impact the accuracy of comparisons. Despite these challenges, the ICD remains an essential tool for monitoring global health trends, assessing disease burden, and informing public health interventions. This study highlights the importance of improving data collection methods, coding accuracy, and healthcare system harmonization to enhance the effectiveness of ICD-based health comparisons. Future advancements in digital health technologies and big data analytics could further strengthen the ICD’s role in global health monitoring and decision-making.