This paper reports on the development of instruments for measuring secondary school student interests in mathematics. Interest in mathematics is regarded as having three components (topics, activities and motives), each with several dimensions. Nearly all instruments employed summated ratings (Likert) procedures, but one adopted an unusual procedure, based on Zuckerman's (1960) Affect Adjective Checklist. Six instruments were developed altogether: IMT (interest in various mathematical topics), ILA (interest in learning activities), MCI (mathematics related career inventory), NMI (nature of motives inventory), GIM (general interest in mathematics) and AAC (affect adjective checklist). The IMT instrument, containing seven scales, was developed to measure students' interests in various mathematics topics, most of which are commonly taught in upper secondary school mathematics courses (eg algebra, statistics). The ILA (three scales) is concerned with interest in various modes of learning mathematics (reception learning, experiential learning, problem solving). The motives component is related to students' reason for studying mathematics; to investigate this component, one instrument (MCI) was developed to measure interest in various mathematics related careers, while another (NMI) explored other possible motives (eg desire for examination success). The GIM and the AAC were designed to obtain general measures of interest in mathematics. All instruments were administered to a sample of 151 Year 10 students in three Melbourne schools; the data were subjected to item, scale and factor analyses. The findings provide good general support for the conceptualisation underlying the study. Factor analysis indicates that there are distinct topic based patterns of interest in mathematics. Eight clear factors emerged, displaying a reasonably good fit with the seven topics originally proposed. There was also good support for the conceptualisation of the learning modes instrument, although the reception learning scale split into two factors (inside and outside the classroom). Three career factors were identified (academic, technical and business).