SMA Muhammadiyah 1 Purwokerto is one school in Purwokerto who routinely doing majors selections. Majoring is intended that students can finish school later in accordance with their interests and abilities before proceeding to a higher level. Selection of Majors currently has drawbacks such takes a long time and the results are less accurate because it could happen a lot of mistakes and subjectivity is quite high because of the criteria used is less relevant. Therefore we need decision support system to assist Master Counseling (BK) in determining the selection of majors. In this research using Simple Additive weighting method (SAW). The criteria used are Mathematics UN Value, Bahasa Indonesia UN Value , English UN Value, IPA UN Value , IPS UNBK Value, Student Interests in IPA, Student Interests in IPS,. The results of this research found that the decision support system with SAW method is able to overcome the problems of Major Selection in SMA Muhammadiyah 1 Purwokerto.