Adult-onset asthma is an important but relatively understudied asthma phenotype and little is known about its natural course and prognosis. The remission rate is believed to be low, and it is still obscure which factors predict remission or persistence of the disease. This study sought to determine the remission rate and identify predictors of persistence and remission of adult-onset asthma. Two hundred adult patients with recently diagnosed (<1year) asthma were recruited from secondary and tertiary pulmonary clinics and prospectively followed for 5years. Clinical, functional, and inflammatory parameters were assessed at baseline and at yearly visits. Asthma remission was defined as absence of asthma symptoms for ≥1year and no asthma medication use for ≥1year. Descriptive statistics and logistic regression analysis were performed. Five-year follow-up data of 170 patients (85%) was available. Of these, 27 patients (15.9%) experienced asthma remission. Patients with asthma persistence were older, had worse asthma control, required higher doses of inhaled corticosteroids, had more severe airway hyperresponsiveness, more often nasal polyps, and higher levels of blood neutrophils as compared to patients who experienced clinical remission. In a multivariable logistic regression analysis, only moderate to severe bronchial hyperresponsiveness and nasal polyps were independent predictors of asthma persistence. Patients with these 2 characteristics had <1% chance of asthma remission. One in 6 patients with adult-onset asthma experiences remission within the first 5years of the disease. Inpatients with moderate to severe bronchial hyperresponsiveness and nasal polyposis, the chance of remission is close to zero.