A system and method for message filtering are disclosed. A conversion target letter table is generated which stores information on letters that may be used to elude filtering, the table storing the hex code information of each letter that may be used for eluding filtering and the conversion letter information regarding the conversion letter to which each letter is to be converted. A hex code of a message text inputted by a user is compared with the hex codes of the table, and when a conversion target letter is included, it is converted to the conversion letter stored in the conversion target table associated with the letter. When the conversion is completed, it is determined whether or not pre-configured prohibited words are included in the converted message; and message filtering is performed.