The purpose of this study was to assess the impact of a teacher professional development program on the classroom teaching practices of the participants. This particular professional development program included an intensive summer institute, 8 monthly follow-up sessions, informal participant-professor mentoring and peer networking. The majority of participants were teachers (grades 4-8) in rural school districts. Qualitative and descriptive measures were used to assess the impact of this program in terms of participants' science content learned, teacher self-efficacy, classroom teaching performance and an informal program survey.