The aims of this study is to improve the learning outcomes of biology class X through jigsaw cooperative learning in SMK Negeri I Mendo Barat academic year 2018/2019. Data analysis used is a descriptive comparative analysis which means comparing the value of the test results in the pre-cycle condition with the condition after the second cycle Data collection was obtained from the initial conditions, the results of cycle 1 and cycle 2, because the class actions carried out consisted of two cycles. Then, the data analysis for each cycle was carried out inductively by comparing the learning process with the same Jigsaw method. The results of the study showed that there was an increase in the test results of students from the initial condition to cycle 1, which was egual to 31,73% ( average value from 5,64 becomes 7,43). Then from cycle 1 to cycle 2 also experienced an increase in replication value of 5,42% or from 7,43 becomes 7,82. In other words, after the class action there are two replication value cycles there is an increase of 38,65% ( 5,46 becomes 7,82). Thus jigsaw cooperative learning can improve biology class X learning outcomes in SMK Negeri I Mendo Barat academic year 2018/2019.