Given issues related to differences in learner characteristics, effective sampling across the content domain, and recent emphases on assessing meaningfully contextualised abilities and higher-order cognitive processes, the "traditional" mathematics test arguably does not provide a valid measure of student ability. Consequently, there is a need to incorporate alternative methods of assessment that are able to effectively assess the range of students' mathematical abilities. The present study investigated methods of assessment used by 60 mathematics teachers from 11 secondary schools in metropolitan Sydney, as well as their attitudes to a range of alternative assessment methods, together with reasons why they would or would not implement these. Results showed that teachers were satisfied with traditional tests as valid measures of student ability, particularly for senior school years. Teachers generally did not favour implementing alternative assessment methods, although those with the least years' teaching experience reported more positive attitudes. A major concern raised by teachers about the use of alternative assessment methods related to their perceived subjectivity. Explanations for these findings are advanced for teachers who have varying lengths of teaching experience.