In this final thesis entitled „Depression in children“ the aim was to study how humor and optimism affect and influence on depressive conditions in preschool children. Depression will easily come by itself, if we allow that to happen. Depression in preschool children can be manifastated as a disease, but it can also appear in a form of a mood, a syndrome and as a disorder. Unfortunatelly, most of the children are challenged with those depression conditions. In a scientific way appears that the boys were more depressive comparing with the girls, but in the other hand the adult women were far away depressive than adult men. In the last century the depression which was recorded during different researches significantly increased in adults, but in children too. Depression is recognized by specific symptoms which are defined and different for each group. There is a large spectrum of causes for depression. Depression is a disease that can be cured. It's very crucial to educate the parents and the kindergarten teachers because their support is very important in the child recovery from depression. Children, and especially younger age children are satisfied if they feel safe, if they have control and power over things, positive surrounding and if they have ability to act, unlike that children tend to lean to depression when their power is denied, act without effect, and when they are without safety. To earn an award is one of the best positive stimulation for child self-esteem and progress. The style of explanation in optimistic child is also optimistic. Pesimistic style of explanation can be turned into optimistic and the child can be encouraged to learn how to become optimistic. Expression of sadness has to alarm kindergarten teacher because of potential development of depression. It's shown that the humor and optimism help and are like a prevention in the treatment of depression. Using humor and optimism preschool children rarely reach in depression conditions and they experience a whole sequence of positive mentally effects such as: reducing stress, anxiety, fears and conflicts. The role of preschool teacher in that processs is to transfer and bring humor in a interesting way to children.