BACKGROUND Mometasone furoate (MF), a potent synthetic inhaled corticosteroid (ICS) with a high affinity for the glucocorticoid receptor, is approved for use in the treatment of asthma. SCOPE Publications reviewed in this article were identified via searches of MEDLINE and EMBASE databases using the terms 'mometasone furoate AND pharmacology' and 'mometasone furoate AND asthma AND clinical trial'. Data from abstracts presented at respiratory society meetings, and relevant background information, are also reviewed. FINDINGS In clinical studies, MF, administered by dry powder inhaler (MF-DPI), was effective in treating all severities of persistent asthma, improving pulmonary function, reducing asthma symptoms, and reducing or eliminating the need for oral corticosteroids. Once-daily dosing of MF-DPI was effective in patients with mild or moderate persistent asthma previously taking twice-daily regimens of inhaled corticosteroids (ICSs), and in patients taking only inhaled beta2-agonists for symptom relief. Once-daily dosing in the evening with MF-DPI 200 microg conferred a greater benefit than morning dosing with MF-DPI 200 microg. Patients with severe asthma who were dependent on oral corticosteroids (OCSs) and high doses of ICSs were able to achieve greater asthma control and reduce or even eliminate OCSs when switched to MF-DPI. In trials of up to 1 year in duration, MF-DPI was well tolerated, with the majority of adverse events considered mild or moderate in intensity. MF had low systemic bioavailability and no clinically significant hypothalamic-pituitary-adrenal-axis suppression at therapeutic doses. The DPI device is a multiple-dose inhaler with a counter containing agglomerates of MF and lactose. Patients of all severities of persistent asthma were able to generate and maintain airflow profiles necessary to provide a uniform and accurate dose. LIMITATIONS Only one study evaluated both morning and evening administration of once-daily doses, and one of the comparative clinical trials was an open-label study. CONCLUSION Once-daily administration of MF-DPI 200-400 microg in patients with mild to moderate persistent asthma effectively improved lung function and asthma control. In patients with severe persistent asthma dependent on oral corticosteroids, treatment with MF-DPI 400 microg BID permitted substantial reduction of oral corticosteroid use. All MF-DPI treatments were well tolerated and had minimal systemic effects.