Acute severe asthma is a potentially fatal emergency usually encountered in the ICU that should be diagnosed and managed properly in order to decrease the risk of morbidity and mortality.Understanding the pathophysiology of asthma has aided in development of new modalities of diagnosis and treatment.The diagnosis is essentially clinical and there is no diagnostic test to rule out the diagnosis of asthma.Beta agonists are considered the cornerstone in management of acute severe attacks together with anticolinergics and corticosteroids. Other drugs that are effective in controlling the attack include magnesium sulphate, adrenergic agonists and heliox.Appropriate timing of introduction of ventilation whether non-invasive or invasive and using optimal parameters results in a better outcome.