This paper reflects upon the empirical implementations of class concepts in cross-sectional research focusing on the aspect of basic and construct equivalence in line with Bachleitner et al. (Methodik und Methodologie interkultureller Umfrageforschung. Wiesbaden: Springer Fachmedien Wiesbaden). Based on a review of the main historical theories, the most prominent empirical applications and a selection of newer empirical operationalization attempts are assessed with regard to functional equivalence across countries. The conclusions indicate a rather good level of equivalence, but only if implemented in the strict occupation-based fashion of class analysis. It is argued to depart from the strict implementation towards a multidimensional understanding of class. Meanwhile, the article demonstrates how cross-sectional research can benefit from the framework of functional equivalence by Bachleitner et al. (Methodik und Methodologie interkultureller Umfrageforsc- hung. Wiesbaden: Springer Fachmedien Wiesbaden).