In argumentative writing, the presence of logical fallacy, which can be simply defined as error in reasoning, shows either illegitimate arguments or irrelevant points that will undermine the strength of a claim. Despite its significant role in determining the quality of an argument, the topic of logical fallacy has not been widely explored in the context of EFL, the possible reason being the fact that there are other aspects that need more immediate intervention, such as grammar, organization, or mechanics. The objective of the current study is to identify and discuss logical fallacies in the argumentative writing of Indonesian EFL learners. For this purpose, 40 argumentative essays written by the students of the English Department of State University of Malang were analyzed. An FGD discussion involving students who participated in the essay writing process was organized following the identification of logical fallacies in their writing. The results of the study showed that students still produced a number of logical fallacies in their work, some of which were very basic they can actually be avoided through simple, explicit instruction. A bibliography is included.