In initial teacher education (ITE), preservice teachers acquire declarative knowledge in different knowledge domains: general pedagogy, content, and pedagogical content. To investigate how they use this knowledge in a school-related situation, n = 56 preservice teachers were asked to evaluate a peer's fictitious lesson plan. Their comments were subjected to content analysis and frequency analysis, which identified three distinct clusters reflecting different thought patterns. Participants referred predominantly to pedagogical knowledge, as well as some pedagogical content knowledge; exclusively content-focused comments were rare.