The main aim of this diploma thesis was to identify the international sales contract with a focus on the definition of the international sales contract, the sources of law which govern the international sales contract and the United Nations Convention on Contracts for the International Sale of Goods, with a closer focus on the formation of the contract and rights and rights and obligations of the buyer and the seller under the Vienna convention and the relevant case law for these issues, as well as the gaps in the Vienna convention. The methods used to develop this diploma thesis are analysis, description and synthesis. Analysis is used to the greatest extent in the third chapter, description is used especially within the first and second c...