Asthma is considered as heterogeneous multidimensional disorder due to variable phenotypic presentation. Phenotype is defined as a cluster of either clinical or pathologic features, which tends to be associated with the understanding the mechanisms of the disease. Asthma is typically characterized by airway inflammation, variable airway obstruction, bronchial hyper-reactivity, smooth muscle hypertrophy and apparent reversible airflow obstruction by bronchodilators. ‘Asthma syndrome’ is a term to describe complex pathophysiology of the condition which is not exclusive to allergen triggered episodes. Diagnosing childhood asthma is difficult, due to the similarity of symptoms and overlapping with other wheezing conditions. The precise mechanism for asthma exacerbation, for each individual phenotype is not fully understood. However, it is influenced by genetic interaction with variety of external environmental stimuli. The current understanding on asthma phenotypes were interpreted based on age of onset, associated triggers, clinical aspects, physiologic parameters and type of inflammation (Table 1). Due to the illdefined of the current phenotypic definition and disagreement among the respirologists, it is becoming a challenge to label specific phenotype with certainty. Accurate definition of each phenotype should therefore be helpful to provide better understanding of different mechanistic pathways and focusing on targeted therapy for individual phenotype. (Copied from article).