Bronchial asthma (BA) in children is a difficult diagnosis, and that is especially true for patients in the first six years of life. According to the GINA experts, among the reasons for difficult asthma diagnosis are high prevalence of wheezing, especially under the age of 3 years; limited availability or absence of pulmonary function tests, wherefore asthma diagnosis is based on complaints, medical history and examination, and often on a third-party impression; the existence of different phenotypes of asthma. Both the medical community and parents mistakenly believe that up to 6 years of age the diagnosis can not be established. As a result, for many years patients are followed-up with alternative diagnoses and do not receive the necessary treatment. That means poor control of the disease, repeated exacerbations and hospitalizations. The review presents findings which dispel the afore-mentioned medical myths about the predictors, diagnostic criteria of asthma in children, under-diagnosis, treatment difficulties and errors.