The concept of Intertextuality has appeared on the hand of Julia Krsiteva (1977-1979) who had not brought this concept out of nothing but rather depending on the work of previous researchers. She, moreover, made the door open for other researchers to explore this concept. Therefore, many researchers have written about the theoretical background of this concept as well as its applications. The Arab critics moreover, have their own achievements in enriching the theory and the applications of this concept. The phenomena of Intertextuality have become a real fact which cannot be denied or ignored when dealing with literature texts, specially that its existence in the modern literature has become a well-known fact. The critic, therefore, has to accept it and dig inside its components to know its sources, types and ways to achieve it. This study,which has combined the theory and the application of this concept, is to bring the greatest presence of this concept in modern poetry. In order to prove this presence, we have chosen Nizar Qabani poetry which has many applicable illustrations as well as his rich poetic innovation which has different types of poetry purposes. In order to achieve the goal of this study, we have divided the study into four theoretical and applicable sections. The first section has dealt with the theoretical part of the concept in which we have shown the beginning of the concept in western literature and its roots in Arabic literature and the role of critics to set its theoretical background. In the second section we have discussed the sources of the concept in Nizar Qabani's poetry. In the third section, moreover, we have discussed the direct and indirect types of Intertextuality in Nizar's poetry. In the fourth section we discussed the mechanisms in Nizar's poetry which we have divided them into two parts: personality recalling mechanism and text recalling mechanism This study has proved the importance of the Intertextuality phenomena in studying poetry in general and the modern poetry in specific since it is hardly to find a poetic text without the application of this phenomena in its different types, techniques and mechanisms.