The publication analyzes the provisions of the current legislation that determine the relations of the parties under a simple partnership agreement (joint activity agreement). Particular attention is paid to the issues of accounting for joint activities, as well as the peculiarities of taxation of operations carried out within the framework of such activities. Separate sections of the book are devoted to the peculiarities of accounting and taxation of business transactions within the framework of a shared construction agreement, and the use of toll materials in calculations.