Cognitive and emotional development of children in infant period, the earliest and early childhood are influenced by biological/genetical factors, but also by other external factors stated in this paper. Every one of them is of great importance and presents a precondition for a child's further development. With it's arrival to the world, a small newborn begins exploring it's surroundings and it's own abilities thanks to it's reflexes. Soon after that, it develops an idea about itself, it learns the ideas of size, shape and colours. By the end of it's second year it becomes a being that is confidently achieving it's goals, is solving simple problems and representing it's experiences using speech, gestures and play. A big number of mental abilities, such as attention, memory, making logical conclusions, language and literacy, imagination, creativity and the ability to think about it's own opinion and take a different perspective is strengthened with the help of imagination play. Therefore, in order for a child to have a healthy development, it is necessary to provide a safe, warm and supportive environment. The emotional development of the child also begins with it's birth. The child adapts to the world that surrounds it creating attachments; close contact primarily with it's mother and thus making relations with others. With the increase of a child's ability of independent movement, fundamental emotions such as joy, anger and fear appear, as reactions important for survival. The development of self-realization leads to the development of self-respect, more and more frequent experience of emotions of self-awareness such as shame, sorrow and pride, easier partaking in interaction with others, and thereby the creation of empathy. The ability of mental representation, language development, easier temperament and quality parenting lead to the most effective ways of regulating child's emotions.