This study examines the relationship among size, auditor quality and financial performance of audit firm in terms of an organizational life cycle framework. Path analysis is applied to test the relationships. Empirical data are obtained from the 1998-2004 Survey Report of Public Accounting Firms in Taiwan, published by the Financial Supervisory Commission, Executive Yuan, Taiwan, R.O.C. Findings obtained indicate different objectives of audit firm across different life cycle stage. The life cycle is characterized by three stages: the youth, the adult and the old. During the youth stage, size has more powerful strategic role than auditor quality in creating financial performance. In the adult stage, size is the only way to improve financial performance. However, during the old stage, the only way taken by audit firm to create superior performance is to enhance its auditor quality. Our findings not only contribute to the literature of human resources but also provide the owners of audit firms with useful information for their operating decision-making.