This paper focuses on artistic expression in children and the way it develops as children grow and mature. It will be explained how children express themselves through art; how art helps children to communicate with their surroundings; when the artistic expression becomes one of the most important ways of communication and how it becomes more detailed as the years go by. Furthermore, an explanation will be given for what certain forms of artistic expression mean; for the importance of freedom in children’s artistic expression; for how much influence freedom has on children's way of expressing and building their own personality, because freedom is very important in spotting the problem and can be very important in the attempts to communicate with children. This thesis will provide an explanation for diagnostic purposes of child’s drawing; it will point out the art therapy as a form of non-verbal communication which helps to characterize a child, more precisely, to find a reason for child’s suffering or pain. The artistic expression, the drawing as the means of expression, has an important role in detecting aggression and trauma caused by some form of abuse that a child may have endured and it can be seen in the symbols an abused child uses while drawing certain motifs like human figure, face, house, family, tree and more. Enabling children to express themselves through art creates an opportunity for them to strengthen their self-confidence and provides an insight into child’s inner world. The purpose of this paper is to emphasize the importance of children’s drawings and the artistic process as one of the most important indicators for the presentation of child’s inner state. Through art, children subconsciously show what they have gone through, what bothers them or what they are unable to communicate through spoken language. Through artistic expression and freedom that goes along with it, children can “talk” about their inner world. Knowing the signs and symbols which indicate the need for art therapy, children are given much needed help in order to better diagnose their drawings and receive help with solving the problem they face.