The results of the data analysis showed that there are statistically significant differences in the usefulness of authentic materials as compared to instructional materials in terms of vocabulary acquisition in favor of authentic materials. The interview and the questionnaire revealed that the participants showed great interest towards authentic materials. Authentic materials helped to increase students' comfort level and self-confidence when dealing with the target language vocabulary Generalizing the results upon EFL Armenian pre-intermediate level students, it should be noted that the effectiveness of authentic materials o vocabulary acquisition is highly dependent upon such. factors as difficulty materials students' background knowledge, topics of the classes, the accompanying activities and many others.