Purpose: The aim of this study is to empirically analyse how motivation and the opportunity to investigate enhance the direct relation between the researcher’s human capital and individual scientific performance.Design/methodology/approach: Following recent investigations of strategic human capital and the abilities-motivation-opportunity (AMO) theory, we propose a double quantitative-qualitative methodology to identify the determinants of individual scientific performance.Findings: Applying regression analysis to a sample of 471 Spanish academic researchers, we confirm the moderating role of a researcher’s motivation and opportunities.Originality/value: Drawing on the empirical evidence obtained, this work discusses the relevant determinants of scientific productivity, providing practical recommendations for research management and policy making.