There is considerable research on teachers' beliefs and teachers' knowledge, but little empirical evidence exists as to the interplay between them. This article reports a study of 356 Norwegian teachers who answered a questionnaire and a multiple-choice test. Based on this study, the connections between two knowledge constructs and two beliefs constructs are examined. The findings demonstrate how different emphases on rules and reasoning are connected to different aspects of mathematical knowledge. (Contains 10 tables and 3 figures.)