Abstract: There is provided a method of electronic business transaction using hardware identification numbers, which includes a step 1 of extracting a hardware identification number from the hardware of a user computer, a step 2 of transmitting the extracted hardware identification number to a server; and a step 3 of generating an identification number account based on the transmitted hardware identification number in an identification number account database of the server, the database containing information about identification numbers of user computers, and confirming the existing identification number account with the transmitted identification number to use the identification number account as a user account when an identification number account having the same identification number as the transmitted identification number has already existed in the database.