Abstract: The present invention relates to a method and system for authenticating products using serial numbers and passwords over a network, which can determine whether the products are genuine based on the serial numbers, which are attached to the respective products, and the passwords, which can be viewed at the time of unsealing the products. When the present invention is used, authentication for a product is performed according to whether the serial number and password of the product match and whether a request for the authentication of the serial number has been made, and thus a reliable authentication system can be provided. Furthermore, one or more passwords for the product are sealed in or attached to the product, so that, if the password is not known, an imitation is distinguished as not being a genuine product, therefore an effective authentication system can be provided.