The federal No Child Left Behind Act of 2001 (NCLB) calls for a highly qualified teacher in every classroom. According to the legislation, "highly qualified" is defined as full certification, a bachelor's degree, and demonstrated content knowledge in all core subjects taught. States, district, and schools are spending considerable resources addressing these provisions, but to what degree are the readily available measures of teacher qualifications associated with the type of teaching advocated by standards-based reform? The authors examine the relationships among educational credentials, preparedness to teach content, participation in professional development, and use of reform-oriented instruction by middle school mathematics teachers using data from the 2000 National Assessment of Educational Progress (NAEP). Their analyses suggest that preparedness to teach mathematics content and participation in content-related professional development activities are associated with reform-oriented teaching, measured here as increased emphases on conceptual learning goals for students and increased use of reform-oriented teaching strategies. (Contains 4 figures, 11 notes and 6 tables.)