Mathematical problem solving is regarded as the one of the important cognitive activities. Children are introduced with mathematical word problems that require reading and understanding in the first grade. Students have trouble with word problems in every level of education. For this reason, it is important to find the reasons for this issue in the first year of primary school. The purpose of this study is to find the relationship between mathematical problem solving with early math skills and reading comprehension. Specifically, the aim of this study is to determine which of these variables are most powerful in predicting mathematical problem solving performance. The panel research method as a type of longitudinal study was used in this study. The sample of this study consists of 185 first grades (66-84 month) students from a public elementary school in Istanbul. The measurement instruments are Bracken Basic Concept Scale: Expressive, reading comprehension questions and mathematics problem-solving questions. The final model implies that early math skills have direct effects on reading comprehension (beta=.34) and mathematical problem solving (beta=.45). Reading comprehension has a direct effect on mathematical problem solving (beta=.27). However, this effect is smaller than the effect of early math skills.