This article examines how teachers decide which technologies to use in their classrooms and what they expect to gain from adopting technology. Observation, interviews, and document collection were used to collect data as a part of a research project in a Midwestern state. Subjects were 15 to 25 mathematics professionals participating in the project between 2001 and 2003. Results indicated that there were five criteria affecting teachers: (1) accessibility and availability, (2) applicability, (3) influence of colleagues, (4) teachers' skills/knowledge, and (5) students' skills/knowledge. The findings are discussed in a model of technology adoption in relation to the existing literature. (Contains 4 figures.)