Purpose: The purpose of this paper is to test the validity of the curriculum auditing tool Sustainability Tool for Auditing University Curricula in Higher Education (STAUNCH[C]), which was designed to audit the education for sustainability and global citizenship content of higher education curricula. The Welsh Assembly Government aspires to incorporate sustainability across all sectors and required an audit of all higher education curricula within Wales. The paper also discusses responses to the auditing process, findings at an institutional and national level and proposes recommendations for improvements. Design/methodology/approach: The University of Wales, Newport, provides the case study to test the validity of the STAUNCH[C] software. Findings: The quality and effectiveness of the curriculum content was not identified by the audit. The audit identified what the curriculum offered but did not necessarily reflect that studied by students. Modules offered on more than one course were awarded credit within the "cross-cutting" criteria of the audit and this distorted the final results. The audit enabled curriculum managers to identify programmes of study which exhibited strengths and limitations in this area. Utilising a common auditing tool across the Welsh higher education sector allows for future developments to be collective and collaborative. Practical implications: A general consensus of opinion from a network of Welsh higher education institutions regarding any future use of this auditing tool is currently one of uncertainty as far as any validity the tool may bring to driving the sustainability agenda forward. Alterations to the STAUNCH[C] software and auditing process are proposed if possible future audits are to be more effective. Nevertheless, within a relatively short time span education for sustainable development and global citizenship within Welsh higher education is gaining momentum. Amendments have been made to university documentation, staff-training initiatives developed and the potential impact of curriculum development in this area is beginning to be realised. Originality/value: This paper discusses the application of a new sustainability curriculum-auditing tool and the validity of the tool in progressing sustainability within the higher education sector. (Contains 8 tables and 4 figures.)