The aim of this study is to examine the relationship between the cognitive processing levels of preschool children and their problem-solving skills. The Cognitive Assessment System (CAS), developed by Naglieri and Das (1997) and adapted into Turkish by Ergin (2003), was used to determine the cognitive processing levels of children. A puzzle completion task was given to determine problem-solving strategies of the participant children. The age range of 21 children in the study group was between 5 and 6, with an average age of 5.61 months. According to the coding of the researcher 11 positive and 4 negative puzzle completion strategies that were used by children, were determined. A canonical correlation analysis was conducted using positive and negative strategies as predictors of problem-solving skills to evaluate the multivariate shared relationship between cognitive processes and problem-solving. The results indicated the explanatory percentage of the Planning dimension of cognitive processes on positive strategies was found to be higher than the Attention, Simultaneous and Successive dimensions.