In Iranian law, there are no express regulations on the endorsement of commercial Instruments by an agent. But, this kind of endorsement is valid and in the case the agent has the power to endorse and mentions his position and the principal, he will have no liability towards the holder. in this case, the principal only bears the responsibility.In Geneva uniform jaws on bill of exchange and promissiory note and chech, the endorsement by an agent is not expressly mentioned. But, as regards the conditions for the liability of the agent and principal, by analogy the regulations on the issuance of bill of exchange by an agent are applied and it can be said that the liability is the same mentioned in the Iranian law.In English law, in contrast to the Geneva uniform laws and the Iranian law, the endorsement by representation and the liability of the principal and agent have been expressly mentioned. If the agent endorsed the instruments on behalf of, and discloses the principal, in the instruments and at the same time has the power to do so, then he will not be held liable towards the holder. In this case, the principal only bears the responsibility. In the English law, in contrast to the Iranian law, a third party with good faith enjoys full protection.