The undulation pump is a small, continuous flow displacement type blood pump, and the undulation pump total artificial heart (UPTAH) is a unique, implantable total artificial heart based on this pump. To improve the durability of the UPTAH for investigating long-term pathophysiology with UPTAH, a third model (UPTAH3) has been developed. UPTAH3 was designed to separate the left and right undulation shafts and to be more durable. The undulation pumps were also redesigned. UPTAH3 was implemented with a diameter of 76 mm, width of 78 or 79 mm, total volume of 292 ml, and weight of 620 g. The priming volumes of the left and right pumps are 26 and 21 ml, respectively. The atrial cuffs and outflow cannulae were also redesigned for UPTAH3. The maximum output against an arterial pressure load of 100 mm Hg is about 11 L/min. The maximum pump efficiency is about 15% in the left pump and 18% in the right pump, giving a maximum total efficiency for both of about 11%. To date, UPTAH3 has been tested in 17 goats, and the longest survival period was 46 days. This third model will be useful for investigating pathophysiology with UPTAH.