This thesis describes the contract of sale as an important part of economic branch of commercial law in the case of change of ownership for a certain thing, ie. when the buyer agrees to pay a certain price to the vendor to acquire ownership. The paper first elaborates the rules and mode of operation of the commercial law, then the commercial contract law that regulates social relations in which legal entities are included in order to exchange certain goods and services, as well as its fundamental principles. After that we enter into the issue of the contract, because the conclusion is often preceded by negotiations, which aim to achieve the consent of the will, or to find one point on the line of mutual rights and obligations in which the interests of both parties will be satisfied. The contract of sale is called a contract governed by the provisions of Law of mutual obligations, the purchase contract is concluded when the parties have agreed on the essential elements of the contract that are subject to sales and price, with the object of buying and selling that can be a thing or a right. By concluding the contract obligations, the seller and the buyer take certain responsability from which it follows that the purchase contract bilaterally obliged. The fundamental obligation of the seller handing things in a time and place designated by the contract. The seller is liable to the customer for material defects things that existed at the time of transfer of risk to the buyer. Basic obligations of the buyer is paying and taking things bought. At the end of the work, special types of buying and selling will be described such as buying and selling with the right of first buy, experimental buying, selling/buying by model, with the specification, compliance with property rights and credit terms.