Pulmonary arterial hypertension (PAH) is a disease with a poor prognosis and high mortality rates therefore in the era of advanced therapies targeting different patophysiological pathways attractive seems the idea of combining drugs from two or more classes. They can be applied sequentially or initially (upfront). Data from randomized clinical placebo controlled trials and observational studies show that both strategies can be successful in terms of improvement of functional capacity or delaying time to clinical worsening. The European Society of Cardiology guidelines on pulmonary hypertension issued in 2015 present in detail the role of combination therapy in the management of PAH.