Centre Hospitalier Universitaire Vaudois and University of Lausanne 1 article published in JoVE Medicine Modified Tail Vein and Penile Vein Puncture for Blood Sampling in the Rat Model Laura Charlès1,2,3, Thomas Agius*4,5, Irina Filz von Reiterdank*1,2,3,6, Janna Hagedorn1,2,3, Yanis Berkane1,2,3,7, Hyshem H. Lancia1,2,3, Basak E. Uygun2,3,8, Korkut Uygun2,3,8, Curtis L. Cetrulo Jr.1,2,3,9, Mark A. Randolph1,2,3,9, Alexandre G. Lellouch1,2,3,8 1Vascularized Composite Allotransplantation Laboratory, Massachusetts General Hospital, 2Harvard Medical School, 3 Here, we present a protocol to offer rapid, easy, and reliable blood collection alternatives for the rat model. We describe three different blood sampling methods according to the context: tail vein puncture under anesthesia or on a conscious animal, and dorsal penile vein puncture under anesthesia.