Idiopathic pulmonary fibrosis (IPF), the most common of the interstitial pneumonias, is a progressive, life-limiting disease for which there are no truly effective therapies. In patients with biopsy-confirmed IPF, median survival is still <3 yrs. Although potent immunosuppressive therapy has underpinned the treatment of IPF in recent years and remains the standard of care, there is little quality evidence to support the efficacy and safety of traditional therapeutic strategies. This has spurred the search for new treatments for IPF and has led to a series of clinical trials of new therapies, seven of which are reviewed herein. They include the Bosentan Use in Interstitial Lung Disease (BUILD)-1 trial, the results of which are discussed in detail, the European Idiopathic Pulmonary Fibrosis International Group Exploring N-acetylcysteine 1 Annual (IFIGENIA) trial, the interferon gamma (GIPF-001) trial and the INSPIRE trial, as well as trials of anticoagulant therapy, pirfenidone and etanercept. Treatment trials in IPF are hindered by difficulties in achieving a secure diagnosis of IPF and the lack of validated outcome measures that represent either improvement or progression of disease. These and other limitations are discussed in the present article, as well as how some of these problems might be addressed in future trials. Although few of the seven studies met their primary end-points, marginal trends either on primary end-points or statistically significant trends on exploratory end-points were a recurrent theme in most trials. In the BUILD-1 trial, for example, a trend in favour of bosentan was observed on time-to-disease progression or death.