The National Council of Teachers of Mathematics has challenged all mathematics teachers to use their Standards documents as guidelines for teaching mathematics. Many pre-service programs are now presenting curricula that are Standards-based. Five case studies were used to investigate the teaching beliefs and practices of mathematics teachers who had participated in a Standards-based pre-service education. One teacher held beliefs in alignment with the guidelines of the Standards and effectively implemented them in her classroom regardless of the obstacles. Another teacher strongly held Standards-based beliefs but had difficulty incorporating these beliefs into her teaching practices due to the obstacles of curriculum, high-stakes testing, and classroom management. The other three teachers held mostly traditional beliefs and incorporated traditional teaching strategies. Four of the teachers lowered their expectations of students based on the students’ demographics, such as academic level and socioeconomic status.