Coherence and cohesion are pivotal devices that effectively help a writer to make a good writing. This study investigated the coherence and cohesion of students’ argumentative essay writing in a university in Indonesia. By using a qualitative approach, three argumentative essays of undergraduate students of the English Literature Department of Universitas Teknokrat Indonesia were taken randomly to be analyzed.  The data were in the form of words, phrases, or sentences. Meanwhile, data were collected through documents. As a descriptive analysis, the use of coherence and cohesion were examined and analyzed using Halliday’s (1990) theory. The results show that students’ argumentative essay writings have not satisfactorily achieved coherence through some cohesive devices like the conjunction, reference, ellipsis, parallel structure, transitional terms which are used to link one sentence to the other. Besides, some grammatical errors were also found such as the plural forms, active-passive voice, etc. Implication of the study were also presented.