This study aims to investigate the utilization of marginal costing in managerial decision-making processes. The incorporation of Marginal Costing into Decision Support Systems (DSS) plays a pivotal role in enhancing managerial decision-making within modern business settings. Marginal Costing, an accounting methodology, distinguishes itself by segregating costs into variable and fixed components, emphasizing the incremental cost incurred for producing each additional unit. Its core functionality lies in isolating variable costs, enabling a detailed analysis of how changes in production volume affect costs directly. This framework is crucial in cost-volume-profit (CVP) analysis, forming the foundation for strategic decisions regarding pricing, production levels, and overall business profitability. The versatility of Marginal Costing extends to critical decision-making points such as product pricing, where a comprehensive understanding of incremental costs assists in devising competitive pricing strategies. Additionally, it facilitates decisions regarding make or buy choices, enabling managers to carefully weigh options between internal production and external procurement, thereby optimizing cost structures. In scenarios involving special orders, Marginal Costing evaluates the financial feasibility of accepting orders with prices differing from regular selling prices, ensuring decisions are aligned with overarching profitability objectives. The methodology also proven invaluable in resource allocation, aiding managers in identifying the most efficient use of limited resources based on marginal contributions. Furthermore, Marginal Costing assists in inventory valuation by providing a transparent view of variable costs, thereby enhancing the accuracy of financial reporting. In terms of performance evaluation, the method facilitates variance analysis, providing insights into deviations from budgeted figures and enabling corrective actions. As business environments evolve, Marginal Costing, when integrated into Decision Support Systems, emerges as a dynamic tool that not only enhances cost analysis but also guides strategic decisions across various operational domains. Its application transcends financial considerations, fostering a holistic approach to managerial decision-making in pursuit of sustainable and profitable business outcomes.