The Physical Self-Description Questionnaire (PSDQ; Marsh, Richards, Johnson, Roche, & Tremayne, 1994) is an internationally known instrument for measuring the physical self-concept of adolescents and adults. A validated German translation (PSK; Stiller & Alfermann, 2007) and an English short version based on 40 items (Marsh, Martin, & Jackson, 2010) are available. However, to date, no German inventory has been validated for the analysis of the physical self-concept in middle and late childhood. In this study a questionnaire for measuring the physical self-concept in childhood (PSK-K), based on the PSDQ, is presented. The structure of the questionnaire is tested by an exploratory factor analysis (N = 257 children, class 3). The results of a confirmatory factor analysis (N = 339 children) confirm the 7-factor solution. Moreover, the questionnaire is tested and discussed with regard to the reliability and validity of quality criteria. The PSK-K is shown to be a suitable questionnaire for measuring the physical self-concept of children in primary school.