Professors endorse a symbiotic relationship between research and teaching, but empirical evidence supporting this relationship is inconsistent. Many studies operationalized research and teaching too narrowly to detect the believed relationship. Semi-structured, in-depth interviews were conducted with 27 chemistry professors from a large research-intensive university. Six themes characterized descriptions of how professors' research engagement affects their teaching: it (1) enhances student interest, (2) promotes subject-matter currency, (3) generates research examples, (4) models ways of thinking in the discipline, (5) provides contextualization guidance for instruction and (6) helps them explain difficult concepts. Although most responses were conventional in the kinds of impact they reported, responses reflected professors regarding themselves as having taken some steps toward integrating their knowledge about the subject matter, how it is advanced in their field and how this can enhance their formal classroom teaching. Implications for undergraduate instruction were interpreted within Shulman's framework of teacher knowledge and beliefs.