This paper examines how Korean college EFL students use contrastive conjunctions in their argumentative writing in comparison with native speaker college students’ use of them. The data consists of a Korean college students’ writing corpus, which was divided into a lower proficiency group and a higher proficiency group, and an American and British university students’ writing corpus. The findings reveal that the first two most frequently occurring forms are but and however in all four groups,although the usage patterns such as positioning differ between the NS and the NNS groups. The third most frequent form is on the other hand in both NNS groups and yet in both NS groups, which shows an interesting difference in that the NNS groups hardly use yet in their writing. Both NNS groups also show frequent misuses of conjunctive adverbials such as in contrast, on the contrary, and on the other hand. The paper concludes with some pedagogical implications and suggestions.