Background: Long-term follow-up after transition to oral agents from parenteral prostanoid therapy has not been well characterized. Methods: We reviewed our long-term experience after oral transitioning in patients with pulmonary hypertension. Patients were weaned off parenteral therapy based on a pre-determined outpatient protocol. Data were collected retrospectively after transition had taken place. Results: Twenty-one transitioned patients were identified. Fifteen patients (71.4%) were successfully transitioned (ST): 7 to bosentan, 5 to bosentan and sildenafil, and 3 to sildenafil. Six patients failed transition (FT). None of the patients in the FT group received sildenafil. Prior to transition attempt, patients in the ST group were treated with parenteral agents for a mean of 26 months vs. 16 months in the FT group (p=0.12). Maximal epoprostenol dose was low in both groups (ST 17.8 ng/kg/min vs. FT 14.5 ng/kg/min). Mean duration of oral therapy prior to transition was 11 months. After a mean follow-up of 24 months, most patients on both groups were able to maintain stable 6 min walk distance and hemodynamics. FT was not associated with short- or long-term adverse events. Conclusions: Oral transition from parenteral prostanoid agents can be safely done in a selected group of patients. Most patients are able to maintain stable functional class and hemodynamics at long follow up regardless of success of transition attempt. Combination therapy with sildenafil appears to be associated with higher likelihood of successful transitioning. © 2008 Elsevier Ltd. All rights reserved.