SummaryThe asymmetric distribution of amino‐containing phospholipids in plasma membranes is essential for the function and survival of mammalian cells. Phosphatidylserine (PS) is restricted to the inner leaflet of plasma membranes by an ATP‐dependent transport process. Exposure of PS on the surface of cells serves as a binding site for haemostatic factors, triggers cell–cell interaction and recognition by macrophages and phospholipases. Exposure of PS on the red cell surface plays a significant role in sickle cell pathology. We report the identification of two different isoforms of the aminophospholipid translocase, Atp8a1, or flippase, in the murine red blood cell membrane.