This paper presents a descriptive case study of students’ proficiency in argumentative writing prior to receiving instruction. Data were collected from students at two purposefully sampled traditional denominational schools, a boys’ secondary and a girls’ secondary school in Trinidad and Tobago. Teachers asked students to write an argumentative essay on a topic that they felt was within students’ prior knowledge. However, analysis of those essays revealed that most students needed “intensive support”; only 5.7% of writers needed “some support”. Findings pointed to the need for systematic instruction in argumentative genre features, audience awareness, use of discourse organizers, and cohesive devices. Fewer girls than boys required intensive support of their writing. The findings have implications for teachers’ pedagogical approaches to teaching argumentation, especially the amount of time that may be required for increasing students’ writing proficiency.