Diagnosing bronchial asthma (BA) in children below 5 years of age represents a clinical challenge. The reasons for that, as stated by the Global Initiative for Asthma (GINA) experts, are: high prevalence of wheezing, especially in kids under 3 years of age; the reality that the lung function measurements that are key to diagnosis in older childrenand adults are not reliable in this age group, and the diagnosis is to be based on history, clinical symptoms and examination only, and in many cases - on the impressions of parents and/or other caregivers (relatives or non-relatives of the child). The review presents the data on the epidemiology, predisposing factors, specific features of pathogenesis, phenotypes, differential diagnosis, diagnostic criteria and management of asthma in this age group.