We evaluated the short- and mid-term in vivo performance of the Innovamedica ventricular assist device (VAD), a new, low-cost, paracorporeal, pneumatically actuated, pulsatile blood pump. We implanted the VAD in six healthy sheep by inserting the stainless-steel inflow cannula into the left ventricular apex and suturing the outflow graft to the descending thoracic aorta. The anesthetized animals were supported for 6 hours, and pump performance, hemodynamic parameters, and hemolysis were monitored. The pump maintained a blood flow of 4.4 ± 0.8 L/min and an arterial blood pressure of 76 ± 15 mm Hg. At 6 hours, the plasma free hemoglobin concentration was 5.11 ± 0.6 mg/dl (baseline value, 4.52 ± 0.7 mg/dl). The VAD was easy to implant and deair and performed well during the 6 hour period. After successful short-term results, we similarly implanted the VAD in two healthy sheep for 30 days. The animals reached the scheduled end point without device-related problems. Postmortem examination of the explanted organs revealed small infarcted areas in the kidneys of one animal, but renal function was unaffected; the animal also had two thrombi (3 and 7 mm) on the outlet valve. This device may offer a simple, economical alternative to currently available VADs.