The current study is an attempt to investigate the genre of job application letter using genre-based analysis as a powerful educational tool, in order to improve the teaching of business writing at the tertiary level with reference to third- year management students by raising their awareness of the generic structures and linguistic features of the target genre. In this regard, this research work is based on the theory of genre analysis in ESP; it aims to help future graduates to perceive the discourse of business letter so as to better write the latter in agreement with international conventions. In fact, writing for business and professional purposes presents many challenges to learners as it involves many different areas of knowledge and skills. As a result, students should be prepared in advance for the kind of requirements in order to increase their overall marketability in the Algerian job market. The present investigation is therefore carried out to examine how effective genre-based writing instruction is in helping third year management students at Djillali Liabes University improve their low level in business letter writing as well as their own negative attitudes towards the writing skill in general. Accordingly, four chapters have been devoted to this study, the first chapter provides a review of related literature, the second one is devoted to the description of the target situation and population involved, with a special emphasis on the research design and data collection instruments used. The third chapter tries to analyse the results obtained and confirm the hypotheses raised in this work. Finally, the last chapter conta ins some recommendations on how to design and plan ESP writing courses for developing students’ sensitivity or awareness to diverse business genres; it also provides some genre-based writing tasks to raise the students’ consciousness to the move-structure aswell as the linguistic features of a given genre.