Idiopathic pulmonary fibrosis (IPF) is a progressive disease, with a median survival time of 2-5 years. The search for effective treatment has involved numerous clinical trials of investigational agents without significant success. However, in 2011, pirfenidone was the first drug to be approved for the treatment of IPF in Europe. Four key clinical trials supported the efficacy and tolerability of pirfenidone. In the two recently published Phase III CAPACITY trials evaluating pirfenidone (studies 004 and 006), patients with mild-to-moderate IPF were treated with pirfenidone or placebo. Study 004 and pooled analysis of primary endpoint data from both studies showed that pirfenidone significantly reduced decline in percent-predicted forced vital capacity (FVC) compared with placebo (p<0.005). Evidence of beneficial effects of pirfenidone treatment was also observed with regard to several secondary endpoints. Pirfenidone was generally well tolerated, with the most common side effects being gastrointestinal and photosensitivity. Data from the RECAP extension phase of the CAPACITY studies, where patients were treated with pirfenidone for up to three years, further support the manageable tolerability profile of pirfenidone. The efficacy data, coupled with long-term safety data, provide further evidence of a clinically-meaningful treatment effect with pirfenidone in patients with IPF.