There are now many guidelines that provide direction for the diagnosis and management of asthma and chronic obstructive pulmonary disease (COPD). However, both diseases are still underdiagnosed (or misdiagnosed) and undertreated. There is considerable evidence that treatment with anti-inflammatory drugs reduces morbidity and mortality in asthma. The evidence is growing regarding their effect on slowing the remodelling that occurs in subsets of asthmatics. COPD is more challenging. There are no disease-modifying drugs available yet that will change the natural history of COPD. However, there is overwhelming evidence that smoking cessation will slow the progression of disease. Until better drugs are available for the treatment of COPD, emphasis must be placed on primary and secondary prevention by reducing exposure to noxious agents (cigarette smoke in particular). Inhaled corticosteroids appear to have a place in the management of severe chronic obstructive pulmonary disease, perhaps by decreasing the frequency of exacerbations.