Project Cost Management is the process of planning, estimating, budgeting, financing, funding, managing, and controlling costs to ensure a project is completed within the approved budget. It involves three key processes: cost estimation (predicting financial resources needed), cost budgeting (allocating funds to project activities), and cost control (monitoring expenditures and making adjustments to prevent overruns). Effective cost management helps maintain financial efficiency, maximizes resource utilization, and ensures project success while meeting stakeholder expectations.