This article deals with the euthanasia debate in light of new life-sustaining technologies such as the left ventricular assist device (LVAD). The question arises: does the switching off of a LVAD by a doctor upon the request of a patient amount to active or passive euthanasia, i.e. to ‘killing’ or to ‘letting die’? The answer hinges on whether the device is to be regarded as a proper part of the patient's body or as something external. We usually regard the switching off of an internal device as killing, whereas the deactivation of an external device is seen as ‘letting die’. The case is notoriously difficult to decide for hybrid devices such as LVADs, which are partly inside and partly outside the patient's body. Additionally, on a methodological level, I will argue that the ‘ontological’ arguments from analogy given for both sides are problematic. Given the impasse facing the ontological arguments, complementary phenomenological arguments deserve closer inspection. In particular, we should consider whether phenomenologically the LVAD is perceived as a body part or as an external device. I will support the thesis that the deactivation of a LVAD is to be regarded as passive euthanasia if the device is not perceived by the patient as a part of the body proper.