This study sought to determine the degree of congruence between a planned curriculum and that actually being taught in one large midwestern suburban school district and the implementation tasks employed by teachers. In measuring curriculum congruence it was found that, while the district expects fidelity of its planned curriculum, adaptation by teachers at the various grade levels for their school was a common practice. The investigation revealed a lack of congruence between the district's specified curriculum and what was being taught, especially at the secondary level. In the second stage of the investigation it was discovered that teachers' beliefs and practices about the importance of and the participation and involvement in curriculum implementation tasks were more pronounced for those who were most closely attending to the curriculum prescribed by the district. The results of this study indicated a need for further research to investigate teacher beliefs and practices about curriculum implementation tasks in relation to the nature or characteristics of the curriculum being implemented, the expectations of the adopting unit, and the support system for implementing the pre-specified curriculum. (JD)