Children s early mathematical competencies are associated with beneficial mathematical activities in the familial context. However, in surveys used to assess the home numeracy environment (HNE), social desirability is often a problem. Therefore, this study develops a more objective checklist: the Mathematical Title Recognition Test for Kindergarten Children (TRT-Mathe-K). In an online pilot study, N = 76 parents filled in a list of 87 children s games. The results led to the development of two parallel versions of the TRT-Mathe-K. We included only games with at least one nomination and a discriminatory power > .2. In a study with N = 193 families, we tested kindergarten children regarding their nonverbal intelligence, linguistic abilities, and mathematical competencies and surveyed their parents regarding their family background and the HNE. The TRT-Mathe-K proved to be an economical, reliable, and valid assessment tool for assessing the use of mathematical games in the HNE. Further, the TRT-Mathe-K was significantly associated with children s early mathematical competencies and predicted these competencies even after we controlled for child and family variables.