Epigenetics is an emerging field of research and clinical trials in cancer therapy that also has applications for pulmonary arterial hypertension (PAH), as there is evidence that epigenetic control of gene expression plays a significant role in PAH. The three types of epigenetic modification include DNA methylation, histone modification, and RNA interference. All three have been shown to be involved in the development of PAH. Currently, the enzymes that perform these modifications are the primary targets of neoplastic therapy. These targets are starting to be explored for therapies in PAH, mostly in animal models. In this review we summarize the basics of each type of epigenetic modification and the known sites and molecules involved in PAH, as well as current targets and prospects for clinical trials.