Micrococcus is a common cause of bloodstream infection in patients with pulmonary hypertension (PH) on intravenous epoprostenol, but it is rarely reported in other groups of patients. We reviewed the blood cultures of all patients with PH on continuous epoprostenol infusion through a Groshong catheter treated at our institution from 2001 to 2006. Thirty-one (33%) of 93 patients with PH requiring epoprostenol infusion had a total of 45 bloodstream infections. Staphylococcus aureus and Staphylococcus epidermidis accounted for 21 (46%), followed by Micrococcus species with 5 cases (11%). No episodes of micrococcal bloodstream infection were identified in 657 patients without PH requiring Groshong catheters for other conditions during the same period. All isolates were susceptible to vancomycin, and in 1 case resistance to penicillin appeared 4 weeks after the treatment. No patient died as a consequence of the infection.