This paper examines the development and implementation of the Malaysian Integrated Science course in relation to patterns of assessment. After reviewing briefly the nature of the programme, it considers ways in which the course appears to have been affected by the form and content of the selection examination held at its completion. The paper concludes by arguing the importance of: i) developing techniques of assessment and examination which correspond systematically with the educational objectives of new curricula; ii) close monitoring of the workings of selection examinations and their effects on the curriculum; iii) detailed and explicit feedback of examination performance to teachers and pupils.