The use of devices for measuring the exhaled fraction of nitric oxide has proven to be very useful, especially in the diagnosis of asthma, prediction of response to corticosteroids, risk of exacerbations or compliance with treatment, among others, and their use is recommended by important clinical practice guidelines. In recent years we have witnessed a proliferation of options on the market with different characteristics. To help in choosing a device that suits the needs of the professionals involved in the management of asthma, this review presents some of the important characteristics of the most common devices. In addition, the existing comparative and pharmacoeconomic studies are analyzed so that professionals can make the choice of device guided by the most current evidence.