Pulmonary arterial hypertension (PAH) is a disease that imposes a significant burden on patients. Although multiple treatment options for PAH are available, head-to-head comparisons are difficult to conduct. Network meta-analysis (NMA) can be a useful alternative for direct comparison to estimate the relative effectiveness of multiple treatments. The objective of the present study was to conduct a systematic review and NMA to evaluate the relative effectiveness among oral PAH medications.Data collection was performed by searching the Cochrane Central Register of Controlled Trials (CENTRAL) and Ichushi-Web. Randomized controlled trials (RCTs) assessing at least 1 of the following 3 outcome measurements; 6-minute walk distance test (6MWD), WHO functional class (WHOFC), and mean pulmonary artery pressure (mPAP) were included (PROSPERO registration number: CRD42015016557). Outcomes were evaluated by estimating the differences in the mean change from baseline or by estimating the odds ratios. Analyses were performed using WinBUGS 1.4.3.Seven double-blind RCTs were eligible. NMA results showed similar improvements in 6MWD for all medications assessed. Bosentan and sildenafil caused a statistically significant improvement in WHOFC compared to other medications.The relative effectiveness of oral PAH medications could be compared using NMA, which suggested the superiority of bosentan and sildenafil in the improvement of WHOFC.