This study claims that Arab ESL students writing in English transfer L1 rhetorical modes of text organization into their English compositions. Fifty academic research papers were analysed in terms of the transition words and cohesive devices used, on the assumption that differences at the level of these language forms reflect differences at the higher level of rhetorical text organization. The hypothesis is stated in two sub-parts. In the first, it is claimed that, as in L1 native texts, the students' English compositions use a predominantly additive mode of propositional development. In the second part, it is claimed that, as in L1 native texts, propositional connectivity is established in the students' compositions largely through repetition of the same noun, as opposed to the use of grammatical cohesion. The results of the analysis provide strong statistical support for both sub-parts of the hypothesis. Overall, additive transition words are more commonly used in the compositions than other types of transition words. Further, the repetition of the same noun is statistically more frequent as a cohesive device than grammatical cohesion. An attempt is made to explain the rhetorical modes used in the students' compositions as well as in native Arabic texts with reference to Arab culture. (Contains 9 figures.)