Background. Asthma is a heterogeneous condition characterised by chronic inflammation and variable expiratory airflow limitation, as well as airway reversibility. The diagnosis of asthma in young children is limited by the inability to perform objective lung function testing in this group of patients and the wide variety of conditions that can phenotypically present with asthma-like symptoms. Objectives. To provide an evidence-based approach for clinicians to accurately diagnose asthma in young children and to assess the level of control to guide therapeutic decisions. Methods. The South African Childhood Asthma Working Group (SACAWG) convened in January 2017 with task groups, each headed by a section leader, constituting the editorial committee on assessment of asthma epidemiology, diagnosis, control, treatments, novel treatments and self-management plans. The asthma diagnosis and control task groups reviewed the available scientific literature and assigned evidence according to the Grades of Recommendation Assessment, Development and Evaluation (GRADE) system, providing recommendations based on current evidence. Conclusions. Asthma in young children should only be diagnosed if all other causes of wheezing have been considered and excluded, and if there is a response to a therapeutic trial and worsening with withdrawal of asthma medication. Asthma control should be assessed at each visit to guide therapeutic decisions.S Afr Med J 2018