Pulmonary arterial hypertension (PAH) is a frequent complication of connective tissue diseases, such as systemic sclerosis, systemic lupus erythematosus and rheumatoid arthritis. However, the occurrence of PAH in a patient with ankylosing spondylitis (AS) has not been previously reported with a detailed clinical description in the English literature. We herein report the first case of AS associated PAH in a 27-year-old Taiwanese man with a chief complaint of intermittent palpitations lasting for two years. To the best of our knowledge, this is the first reported case of AS associated with PAH with a detailed clinical description and findings of right heart catheterization published in the English literature.