Intertextuality can generally be defined as the effect and presence of previous texts in the structure of the present one; it actually shows the internal relationships of a literary text with all other related texts. There is a consensus that no texts are a complete creation of their authors; rather, they are constructed through a process that links the textual elements of the related texts with the writers’ creativity. In literary genres, intertextuality is employed to play a crucial role. Thus, the writers, un/deliberately, appeal to intertextual elements, elaborate them in their artistic career and creativity to produce the intended text. The study addresses the problem that some readers' unawareness of intertextuality results in misunderstanding and misinterpreting a text filled with intertextual elements. The study aims at investigating the intertextual elements in Mahfouz’s novel Khan al-Kahlili (1946). The hypothesis this study puts forward is that a reader who is well-acquainted with the functions of an intertextual elements is more capable of comprehending and interpreting intertextual texts. As for the analysis of data, the study has adapted Genette's model of intertextuality ( 1997), namely, explicit and implicit intertextuality. It is found that intertextuality is an important and useful device for both the text producers and readers. It is also detected that the phenomenon of intertextuality is utilized by writers of literary genres for various purposes such as: communicative, aesthetic, stylistic and rhetorical purposes.