This research aims at investigating the effect of YouTube videos and pictures as the authentic materials on Indonesian EFL students' writing performance. The experimental research is conducted by using quasi-experimental design. This research employed two groups: an experimental and control group. This is to see which group is effective to be used in helping the students' writing ability. The first group was taught by using YouTube videos and the second group was given treatment by using pictures. Both YouTube and pictures are the authentic materials which help the students to have better writing performance. The subjects of this study were the second semester students of English Department, IKIP PGRI Madiun. Both of the groups were instructed to write a paragraph by using YouTube videos and pictures as the authentic materials. The data were analyzed by using Independent t-test. The result of the study shows that there is significant difference between the students who write a paragraph after being taught by using YouTube videos and by using pictures. The students who were taught by using YouTube videos had lower writing performance than the students who were taught by using pictures. It means that using pictures in teaching writing is better than using YouTube videos to help the students in writing performance. Contains a bibliography.