The current study made an attempt to compare the impacts of teaching authentic materials through traditional techniques with teaching authentic materials through authentic use, where students in the experimental group were taught new vocabulary items of subtitles through watching subtitled videos, and control group were taught the same vocabulary items from subtitles using traditional instruction of vocabulary. The participants of the study consisted of 36 Iranian students from both genders. In order to ensure the homogeneity of the participants, Oxford Placement Test (2004) was administered. Then they were randomly put into two groups (18 students in each group). Immediately after the study and three weeks after the study vocabulary tests were administered to the both groups. The results indicated that the students of control group outperformed in short-term retention. However, the experimental group outperformed in long-term retention, indicating the superiority of learning vocabulary through watching subtitled videos in long-term retention of vocabulary. As many learners do not develop long-term mastery of the vocabulary, teaching vocabulary items through watching videos with subtitles can help them store and retrieve vocabulary items better.