The growing interest in project management as a management approach requires organisations to adopt an operational culture that supports project management principles and practices. The availability of an empirically developed assessment tool would enable organisations to assess their present organisational culture's readiness for project work. The aim of this study is to develop a diagnostic instrument that can measure the operational 'project management culture' in organisations. The final tool (PMCAT) comprises of a five-factor scale. The overall reliability of the items in this scale was highly acceptable with a Cronbach alpha above 0, 70. The tool has a high validity with a inter- item correlation above 0, 32.