This study examined the extent to which external and internal factors influence teachers implementing the National Standards in teaching. Data sources consisted of: (a) observing 26 teachers teaching 78 lessons while taking field notes; (b) conducting 26 formal interviews with the teachers using semi-structured interview questions; and (c) collecting curriculum guides, unit and lesson plans, and assessment sheets if available. All formal interviews were audiotaped and transcribed and all field notes were typed into a computer and printed out for analysis. Constant comparison technique suggested by Glaser and Strauss was used to analyze the data. Trustworthiness was established by triangulating different data sources. Three themes emerged from data analysis. The first theme showed a relationship between knowledge and implementation of the standards. Findings indicated that teachers who were knowledgeable of the standards intentionally used the standards for revamping curriculums, taught to certain standards based on grade levels and content areas, and employed assessment procedures as an integral part of their teaching. Teachers who were only aware of the standards varied in their implementation of these standards. The greatest difference within this group was the conscious effort of integrating the standards into their curriculum. While most demonstrated good practices, only about half were able to consciously relate their teaching practices to the standards. However, few in this group used assessments in their instructional processes. Teachers who were unaware of the standards either unknowingly demonstrated adherence to the standards or actually taught in direct conflict to the standards. The second theme showed a relationship between content knowledge and implementation of the standards. The teachers with a strong knowledge base of developmentally appropriate learning experiences and assessment techniques consistently used the standards in their teaching practices and curriculums. Conversely, the teachers who lacked such a knowledge base failed to teach to the standards. The last theme showed a relationship between administrative support and implementation of the standards. Teachers whose school districts held them accountable for using the standards in their lesson plans and curriculums consciously addressed the standards in their teaching. Teachers whose school districts required them to discuss the standards during in-service programs but did not extend the use of the standards beyond these programs demonstrated little implementation of the standards in teaching. The teachers whose school districts were unwilling to make any changes did not incorporate the standards into their teaching and curriculums, except for one teacher. Keyword(s): national issues, research, standards and ethics