DR. RODNEY McADAM IS A SENIOR LECTURER in the School of Management, University of Ulster, Northern Ireland. The aim of this paper is to determine the critical success factors for the implementation of reengineering in small and medium-sized enterprises (SMEs). Reengineering has developed from a background in large enterprises. Existing methodologies mainly assume a large organisation setting with large-scale resources dedicated to bringing about the large-scale reengineering changes. The literature contains many studies on reengineering theory, applications and critical success factors: however, they are almost all based on large enterprises in either the public or private sectors. The paucity of research involving rieengineering and SMEs comes from two factors. First, reengineering is still a relatively new management approach and has yet to reach SMEs fully from the initial large organisation starting point. Second, there is some remaining doubt as to whether large-scale reengineering is applicable to SMEs owing to resource constraints. The research involves a literature review and an inductive grounded theory approach using multiple case studies. In total, 23 SMEs case studies involving research-based workshops were examined and analysed to determine critical success factors foi reengineering implementationi. The imain findings were that the kev categories of success factorS in reeingineering in SMEs are resctues, miiarket envir-onnment, customerls and(: strategy, leadership, flexibilitv andl change orientationi, structutre, methodology an-d measureinermt. Tiw componen-t factors within these categories were found to diffeir significantly from those of large organisations in a uumbhe of cascs.