Proper nutrition is very important for growth and developing of every human being. Using important nutrients from food, we are ensuring the proper organs work, physical and brain activities, and also we are keeping our immunity strong. Nutrition habits have a big influence on mental and physical health, so it is very important to teach and show children how significant proper and health nutrition is. Hence, the primary goal of this study was to determine how much the fourth-grade students know about principles of healthy nutrition, and what kind of nutrition habits they have as well. Study, which was conducted in June 2016., was attended by 49 fourth-grade students from Elementary School Ostrog in Kaštel Lukšić. Students' knowledge about nutrition habits were examed through three anonymous surveys. Through the detailed analysis of students' responses, it's shown that the students do not understand basic principles of optimal, healthy nutrition. In spite of this, the research has also shown that the students eat healthy food and have well developed nutrition habits. The fact that children dont know enough about food and proper nutrition principles, indicates the need for analysis of the existing content about teaching subjects related to nutrition in early elementary education. Nevertheless, the introduction of new ways of processing these contents will include students in the learning process where they will gain knowledge how to take care of their body and mind healthy, with their own independent research. Importance of healthy nutrition on people's health and development, should be motivating not only for parents and teachers, but also for entire school system. School is an ideal place to acquire and reinforce the knowledge about healthy nutrition habits, especially in the early school period, which can be achieved with quality educational contents that will allow student to gain and apply the knowledge necessary in life, with their own experience.