Abstract: From the perspective of doctrines, legislation (such as civil codes), judicial and other practices, this article examines the rights and obligations of the broker and client in a nrokerage contracts in the countries of the Eurasian Economic Union. The author particularly explores certain obligations of the broker that invoke ambiguous interpretation: obligations of the broker on carrying out client’s assignment; on prevention of the conflict of interests in fulfilment of his professional activity in the stock market; on accounting of client’s funds on a special brokerage account, etc. The scientific novelty consists in comprehensive analysis of the selected circle of questions based on the material of EAEU member-states. The research results consists in determination of the theoretical and practical problems in execution of rights and obligations of the broker and his client on the stock market; formulation of recommendations on the improvement of legal regulation and harmonization of legislation of EAEU member-states in this regard.