This article aims to present the consequences of a State's declaration to opt-out from the freedom of form principle, under Article 96 of the United Nations Convention on Contracts for the International Sale of Goods 1980 (CISG ). In practice, problems have developed as whether or not to apply the freedom of form when a contract is concluded between two business entities, where one has its place of business in an Article 96 CISG reservation State, and the other does not. The issue concerning the reservation's effects has led to the creation of "two schools of thought" established by the doctrine and case law in this respect. It is the author's intention to present the proper methodology of the interpretation and application of Articles 12 and 96 CISG bearing in mind the various opinions in this respect. In the author's opinion, in such situations the court should follow the rules of private international law to seek an answer as to whether or not the obligation of written form applies. Some of the CISG Contracting States that currently maintain an Article 96 CISG declaration, refrain from withdrawal of their declaration despite the fact that the prerequisites for such a reservation are no longer met, as their domestic legal systems do not impose a written form requirement, as was the case at the time when the CISG was negotiated. In the author's opinion, in cases where the rules of private international law point to the law of such a State, the courts should, in practice, refrain from following the Article 96 CISG reservation, i.e. no freedom of form, and should instead apply the less formal domestic law as to the form.