This dissertation is about the rules for taxation of capital gains in regard to the sale of real estate. First the general problems of capital gains taxation and the basic principles of the Swedish capital gains tax legislation are discussed. In the second part of the study, the legislation and case law are examined. Although the legislation is extensive many problems are solved by case law. The basic principles are important for the development of case law. The Swedish income taxation was originally based on the source theory, which excludes capital gains from the income concept. However, limited taxation did occur, with the motivation that sales for the purpose of speculation should be taxed. Since 1966-67 all capital gains on stocksand real estate are taxable. The taxation of these capital gains is now motivated by the ability-to-pay principle. A major problem dealt with in different chapters is the point in time when a capital gain is realized. A capital gain is considered realized when the asset is sold. However, in certain cases the value of the revenue cannot be accurately determined. That part of the price will not be taxed until it can be determined. The situation is the same if the seller retains the right to receive a yield from the property after it is sold The uncertainty regarding the value of this right should result in taxation asthe yield is realized. It should be a general principle that uncertainty regarding the value of the revenue motivates postponement of the taxation. The taxable revenue realized at a sale and the basis for the purchased asset should, in principle, be consistent, so that neither more nor less than the real capital gain is taxed. Gifts of capital assets do not result in any taxation of the transferor. The continuity in taxation is maintained by placing the transferee in the same tax position as the transferor. However, when assets are exchanged, certain problems arise regarding the maintenance of continuity in taxation. The study of the problems mentioned above, as well as others, such as the impact of inflation, the sale of a portion of an asset etc, shows that income is computed in order to show the real capital gain from the sale. This is a basic principle for the legislation and the case law.