This report discusses the justification for the multilateral treaty of the United Nations Convention on Contracts for the International Sale of Goods (CISG) and how it has achieved the legislative achievement of harmonizing private international commercial law. It explores the background of international trade law, the development of the CISG, its aims and provisions, and its impact on international trade. The CISG is a binding agreement that regulates commercial contracts for the cross-border sale of goods and promotes uniformity in international sales.