The aim of the present study is to examine experimentally the influence of using lexical chunks on the achievement of second-year-university students of English in the writing fluency. Lexical chunks, as the composites of form, meaning and function, stored and retrieved as a whole in brain, can release the language processing burden and improve the fluency and idiomaticity of language output. To accomplish this aim, the current study attempts to provide a reply for the following question: does drawing students' attention to the lexical chunks frequently used in different positions help in better success in EFL descriptive essay writing lessons as contrasting to the presently applied method of teaching? Also two null hypotheses are planned. The first states that there will not be a statistically significant difference between the mean scores of the experimental group and those of the control group in the writing performance pretest. While the second one is that there will not be a statistically significant difference between the mean scores of the experimental group and those of the control group in the descriptive essay writing achievement posttest. The two groups pre-test post-test experimental design was adopted. After four weeks of instruction, the findings show that there is a significant difference between the experimental group and the control group in the post-test on the side of the experimental group. Accordingly, the main findings authenticated the first hypothesis of the study, but cancelled the second one. The control group gets the mean score 71.89 while the experimental group gets 76.53. This certainly implies that the use of lexical chunks as a language learning strategy gets better in students' performance in writing fluency