The study presents a review of in-service models and a search for an effective in-service model for mathematics education in the primary school. The study considers the need to improve the teaching of mathematics in the primary school; the major reports that have made recommendations for the improvement of primary mathematics teaching and the opinions and findings of mathematics educators. The study examines the state of the art of in-service models and examines those models previously used. The study notes the failings of the in-service models past and present and examines elements within these models which have proven to be beneficial albeit in part. Throughout the study particular attention is given to recent studies concerned with implementing and sustaining change. The model designed for the in-service of the primary mathematics teacher, MINC (Mathematics In-service Network Course) is based on an examination of models past and present. Components and provisions that have met with success in these models were included in the design. The in-service model developed and described in this study includes four major components input from course leaders and teachers, reflection, feedback and the opportunity for teachers to work with others from the same school and neighbouring schools (networking). A major section of the study examines the responses of participants to an evaluation questionnaire given at the completion of the first in-service course, MINC 1 and the second, MINC 2. Data collected from the responses of participants to the questionnaire were analysed to see if there were differences in responses from teachers based on such factors as sex, the MINC network, the level to which participants had studied mathematics, the year level they taught and expressed confidence in teaching mathematics. In conclusion, the study reflects on the evaluation of the in-service course and addresses considerations for future in-service courses concerned with mathematics education for primary teachers.