This article describes a part of a large scale study which helped to gain understanding of the high school mathematics teachers' belief about proof. There is obvious disconnect between general beliefs and high school teachers' conceptions about proof as central element of mathematics and mathematics education. A total of 374 mathematics teachers from one of the New England states, USA, participated in an on-line comprehensive original survey designed specifically for this study. We report on several units of analysis including teachers' beliefs about proof as a vehicle for developing reasoning skills, proof as a central to learning mathematics, and classroom time spent on proof with different categories of students, and offer some recommendations for teacher professional development and suggestions for further research.