This study assessed the quality of preservice primary teachers' written arguments in a socioscientific argumentation task. Five Australian preservice primary teachers took part in a science content course incorporating explicit argumentation instruction, and numerous opportunities to engage in argumentation. The quality of their written arguments were analysed using a framework adapted from Zohar and Nemet (2002). Results indicated that all five participants engaged in quality argumentation in the socioscientific task, with the majority of participants producing high quality arguments. Other findings indicated that participants' prior experiences may influence the content knowledge they draw upon to support their arguments.