Late-onset asthma is a common disease, with characteristics that differentiate it from childhood asthma persisting in adults, including a heterogeneity of underlying mechanism, a correlation with occupational exposure and the tendency to chronicize. Inadequate perception of the disease importance and difficulties in diagnosis, due to the association to COPD, the broad differential diagnosis spectrum and an atypical clinical manifestation, make this disease entity underdiagnosed and under-treated, with consequences for morbidity and mortality. The treatment of adults with asthma follows the usual guidelines, but must take into account an occasional poor therapeutic response and the risk of side effects in polymorbid patients.