Pulmonary arterial hypertension (PAH) is considered to be a rare but serious complication of bone marrow transplantation (BMT). The majority of the reports demonstrated a potential fatal outcome, while treatments are postulated to require an indefinite duration. Our objective is to describe cases of reversible PAH related to BMT in two patients. Two patients with PAH after BMT were investigated for the common secondary causes of PAH. Both results were negative. The first patient was a 19-year-old male. He was diagnosed with relapse acute lymphoblastic leukemia, underwent BMT, and developed PAH 10 months after transplantation. He was initially treated with iloprost and sildenafil. His functional class gradually improved while his medication was titrated down and switched to amlodipine. His pulmonary arterial pressure has been normalized. The second patient is a 20-year-old female, with a confirmed case of chronic myeloid leukemia, who underwent BMT and developed PAH 4 months after BMT. She was treated with sildenafil and beraprost. With improvement of her symptoms and normal exercise test, her medication was discontinued after 4 months of therapy while her pulmonary pressure currently remains normal. BMT was considered to be an uncommon cause of PAH, which is amenable to reversibility.