Enterprise Resource Planning (ERP) system literature lacks research on post-adoption stages, that is, actual usage. even less studies focus on the specificities of an industry analysis. Based on the Technology-Organizational- Environment (TOE) framework, the present study develops a research model to measure and examine determinants of ERP Use in regards to the impact on Iberian Manufacturing Small Medium Enterprises (SMEs). Hypotheses are postulated based on five determinants (Training, Compatibility, Firm size, Best-practices and Competitive pressure). Testing was conducted through structural equation modeling, utilizing data from 158 web-surveyed firms in Portugal and Spain of the Manufacturing sector. Results showed that all determinants contribute to explain 'ERP Use' except Training. The paper provides insight on which determinants contribute for ERP use in Manufacturing Iberian SMEs, offering managerial and academic implications.