Despite, auditing standards and academic literature emphasising the value of effective communication from the auditor to the audit committee there is relatively scant empirical evidence on its use. We use data from Korea, where communication from the auditor to the audit committee must be disclosed to provide new evidence on the determinants and consequences for audit effort of greater communication. Our results show client risk characteristics and governance are determinants of greater communication, and that communication is associated with higher audit fees and hours. There are differences across audit firms, and between written and face-to-face communication. Our results contribute to both regulators in terms of providing future guidance on communication, and to the developing literature on the determinants of auditor and audit committee coordination.