Increasing emphasis on students' understanding of the practices of science and engineering necessitates that teachers themselves possess a strong understanding of these practices. Unfortunately, a teacher's potentially limited engagement in science and engineering practices throughout his or her own education may impede his or her understanding of these disciplines. Numerous professional development programs aimed at providing teachers with authentic science and engineering research experiences currently exist that may help address this gap. This qualitative study sought to describe, in detail, the research experiences of six teachers who participated in a summer Research Experiences for Teachers (RET) in Engineering program. Results indicate that, even within a single program, teachers' research experiences may be highly varied in both content and structure. This draws attention to a need for further consideration of the design of these types of professional development programs to ensure the advancement of participants' understanding of the practices of science and engineering research.