This investigation is primarily concerned with the In-Service Education and Training (INSET) needs of primary school mathematics educators. The research is grounded in the proposition that in order for senior primary mathematics educators to keep abreast with the current knowledge explosion and rapid rate of technological growth, they are under serious obligation to improve their expertise, knowledge and skills in mathematics teaching and learning through INSET. Pre-Service Education and Training (PRESET) serves only as preparation for entry into the teaching profession and cannot last the whole teaching career. INSET is thus necessary for the senior primary mathematics educator’s continuing education. In this investigation an attempt is made at establishing a framework for INSET and mathematics educators. It is hoped that these theoretical frameworks will enable mathematics educators to cope with the changing needs of senior primary mathematics education. There is no doubt that the developments of senior primary mathematics education and INSET in the United Kingdom can have a profound effect on the senior primary mathematics education in South Africa. The extent to which the developments in the United Kingdom influences the educational initiatives presently being undertaken in South Africa will depend upon those who teach senior primary mathematics and those who are responsible for the provision of INSET of senior primary mathematics educators. The past South African discriminatory policies led to numerous iniquities in the provision of mathematics materials and development of mathematical human resources. Consequently, there is a large number of unqualified and under-qualified mathematics educators especially amongst Blacks in South Africa. It is through INSET that this condition can be rectified. A questionnaire survey revealed that senior primary mathematics educators are fully conscious of the importance and significance of INSET. The recommendations made for the INSET of primary school mathematics educators based on the literature survey and the empirical investigation are: the need to establish a national and provincial policy for the INSET of primary school mathematics educators; there must be a concerted effort to establish school focused INSET; many of the methods of INSET courses emphasizing the participative approach needs to be explored; the value of teachers’ centres as exciting brokers for new ideas and as networks for personnel proves invaluable and finally, pivotal to the INSET of primary school mathematics educators is the need for them to update their in-depth knowledge of mathematics. There is no doubt that the INSET of primary school mathematics educators is a crucial factor in KwaZulu-Natal (KZN). It is clear from this research that INSET for both academic and professional upgrading of the senior primary mathematics educators and the improvement of mathematics teaching and learning I the primary school is only limited by one’s imagination.