This study examines factors related to the sustainability of SimCalc Mathworlds (SCMW), a technology-infused mathematics curriculum. We surveyed middle school teachers one year after their participation in a randomized trial where they were introduced to SCMW curriculum, to identify factors related to their continued use of the materials in ways congruent with the developers' intent. Fifty-two percent of teachers surveyed sustained their use of the SCMW curriculum. Factors related to sustained use included student SES, pre-intervention student mathematics ability, teachers' perceived coherence and perceived utility of the intervention, and the active nature of the SCMW professional development. (Contains 4 tables.)