The past few decades have seen middle school teachers in the United States hit especially hard by contradictory messages about the use and importance of technology in support of their standards-based mathematics teaching. This paper considers this dichotomy with respect to the California Mathematics Education Technology Site (CMETS), a professional development program designed to address the content needs of middle school teachers while addressing relevant issue of technology use in the middle grades. The formation of the CMETS program is described, and its development is grounded around 5 research-based tenets of effective professional development: a focus on teachers as learners, contextual learning experiences, participant collaboration, long-term professional development, and adequate funding. The article concludes with a discussion of the changing role technology must play in the middle grades mathematics classroom. (Contains 6 figures.)