There is a need to consider the impact of the new resident-hours regulations on the variety of aspects of medical education and patient care. Most existing literature about this subject has focused on the role of fatigue in resident performance, education, and health care delivery. However, there are other possible consequences of these new regulations, including a negative impact on decision ownership. Our main assumption of is that increased shift work in medicine can decrease ownership of treatment decisions and impact negatively on quality of care. We review some potential components of decision ownership in treatment context and suggest possible ways in which the absence of decision ownership may decrease the quality of medical decision making. The article opens with the definition of decision ownership and the overview of some contextual factors that may contribute to the development of ownership in medical residency. The following section discusses decision ownership in medical care from the perspective of “diffusion of responsibility.” We question the quality of choices made within narrow decisional frames. We also compare isolated and interrelated choices, assuming that residents make more isolated decisions during their shifts. Lastly, we discuss the consequences of decreased decision ownership impacting the delivery of health care.