This article describes the measurement of socioeconomic status in the first follow-up of the KiGGS study (KiGGS Wave 1) conducted from 2009 to 2012. A multidimensional index score was used. The score is the sum of three metric components: Education and Occupational Qualification, Occupational Status, and Net Income. Compared with the approach in the KiGGS baseline study, some modifications were made in accordance with changes in the other components of the health-monitoring program at the Robert Koch Institute, i.e., the German Health Update (GEDA) and the German Health Interview and Examination Survey for Adults (DEGS1). These changes facilitate the analysis of temporal developments and trends, ensure international comparability of the data, and support the transfer of the results into politics and practice. In order to demonstrate the application of the revised instrument, we report on exemplary results of KiGGS Wave 1 regarding the relationship between socioeconomic status and the general health status of children and adolescents aged 3-17 years.