iSMART (Integration of Science, Mathematics, and Reflective Teaching) Program is an online science and mathematics integrated graduate program for middle school teachers across the state of Texas. As part of a large design-based research project, this paper describes the initial stages of the design process of the iSMART program for its first cohort in the fall of 2010 with a focus on program development. The paper begins with our theoretical perspective and rationale for our use of design-based research methodology. We then provide a review of literature on the integration of science and mathematics and the design of online learning environments. Next, we report on the decisions made by science and mathematics teacher educators in the early process of iSMART design as well as the online design components. Finally, we provide our plan for the continuous implementation and redesign of the program with the first cohort of 25 iSMART teachers. (Contains 1 figure and 3 tables.)