Writing is hard for students who are learning English; they often find it challenging to transform what is on their mind in writing. Therefore, this study examined the relationship between the writing test and assessment writing through argumentative writing. Data was analyzed using the correlation test to determine the close relationship between independent and dependent variables. This study involved 100 students from the Department of English Education at the University of Riau, Indonesia. The results showed that the writing test and assessment writing was closely related, as evidenced by the influence and significance between the writing test and assessment writing, which was tested through argumentative writing. The results revealed that the writing test and assessment writing have similar results. Overall, both variables are equally important and related.