We assessed the influence of genre-specific discourse knowledge and writing goals on the persuasive writing of 4th and 6th grade students with and without learning disabilities (LD). Students were first interviewed about their knowledge of persuasion and persuasive writing. They then wrote a persuasive essay about a controversial topic after receiving either a general goal to persuade or an elaborated goal that focused on the inclusion of elements of persuasive discourse. Finally, the students were asked to generate ideas to assist a hypothetical student who was struggling to write a persuasive essay. Students in the elaborated goal condition produced higher quality persuasive essays than students in the general goal condition. In addition, students with LD wrote less persuasive essays than students without disabilities. Furthermore, knowledge of persuasion predicted the persuasiveness of students' essays. However, the number and types of ideas students generated did not predict essay persuasiveness after accounting for the effects of other variables. Finally, the provision of an elaborated goal did not impact the number or type of ideas generated by the students. However, the students' ideas evidenced considerable sensitivity to possible criticisms that could be leveled by an audience. The implications for argumentative writing are discussed.