Many current environmental problems occur on a planetary scale and their interrelationships are becoming increasingly complex. In order to solve these environmental problems, citizens must be aware of these interrelationships and environmental education plays a fundamental role. The environment must be approached as a complex system that encompasses all the interactions between the elements that form it. This article researches the systemic vision of the environment held by the students of Early Childhood Education in schools in Valencia (Spain). The objective is to find out the level of complexity that 5-year-old children perceive of their environment through their drawings. Drawings made by 224 boys and 197 girls were analysed. The analysis discriminates three categories: abiotic, biotic and anthropic elements. Other subcategories also emerged during the process. The results corroborate a high level of complexity due to the variety of possible combinations of the different categories drawn. Findings that demonstrate that children's drawings are an effective method to know the degree of complexity, based on the systemic vision that students have of their environment.