In this paper several theories, which make different predictions about the effect of board leadership structure on firm performance, are tested. The results indicate that, for Australian listed companies, there is no strong relationship between leadership structure and subsequent performance. It is reported that. companies with higher blockholder ownership or lower managerial shareholdings tend to have an affilIated chairman; firm with higher managerial shareholdings tend to have an executive ch~irman. The evidence suggests that there is no one optimal leadership structure; each structure, w~Ich. C?uld be an outcome of a rational choice process influenced by other governance characteristics of mdIVIdual firms, may have associated costs and benefits.