In this article, we introduce a new dataset-the Comparative Semi-Presidential Database (CSPD)-covering classifications of semi-presidential regimes. In contrast to other databases, the CSPD offers several classifications based on different definitions of semi-presidential regimes along with subtypes of semi-presidential regimes. We use definitions developed by Elgie (in: Elgie (ed) Semi-presidentialism in Europe, Oxford University Press, Oxford, 1999), Cheibub et al. (Public Choice 143:67-101, 2010), Shugart (French Politics 3(3):323-351, 2005) and Shugart and Carey (Presidents and assemblies: constitutional design and electoral dynamics, Cambridge University Press, New York, 1992). Additionally, we present a modified definition of semi-presidential regimes based on the conceptual discussion in the field. The database covers all independent states from 1900 to 2021. Using empirical analyses, we compare the classifications, the importance of conceptualisation and presenting our measurement for semi-presidential regimes.