Spam mail is an email which continuing from thousand of email users and usually contain of product/services/business promotion,pornography,virus and unnecessary emails. Until now, spam mail issues keep blooming by the develipong software as well, email filtering using variant of methods such as naïve Bayesian classification , address block,association rules and other methods. From lost of email filtering methods, seems naïve Bayesian has more accurateness level. In this final exam, writer would like to explain the naïve Bayesian classification method of email filtering. Naïve Bayesian filter was developed by bunch of email which had been classified into spam mail and legitimate. By learning process, the email filtering expected to be more accurate. Keywords : email filtering , Bayesian filter , naïve bayes , spam email, legitimate mail.