Jaguthsing DindyalLearning to write good test items is an important aspect of the teacher preparation programmes in Singapore. This paper reports on the types of errors in writing test items in mathematics made by student teachers who were following the pre-service course for teaching at primary level. An analysis of the errors reveals that student teachers demonstrate some key shortcomings in: Use of language, mastery of content knowledge, use of diagrams as support, and use of appropriate context when writing the items.