In this study, we make the case for using texts children create as part of their play as a means for assessing their developing print literacy knowledge. We assessed 4- and 5-year-old children's authentic texts using categories and criteria from the "Assessing Young Children's Marks/Drawing/Print" tool, a research-based, classroom assessment we co-created with educators. We describe patterns we identified from our assessment of 104 texts the children created as part of their play within six themed centres in three kindergarten classrooms in a small northern town in Ontario, Canada. Overall, our assessment revealed the children's understanding of spelling and the conventions of writing, and of writing as a social practice. However, since many texts were at the single word level, we were unable to determine the children's understanding of conventions associated with more complex texts. We conclude by demonstrating how teachers might use the tool to assess children's play-based texts.