Cardiac assist devices have become an important component of transplantation programs as they successfully bridge unsalvageable patients who would otherwise die. The indications for a device can still be classified into short-term and long-term situations. The short-term indications have expanded into areas such as postcardiotomy failure, high-risk cardiac operations, and acute myocardial infarction with results that were not previously possible in the absence of a well-established mechanical assistance program. Appropriate patient selection remains challenging and perhaps the most important attribute of a successful ventricular assist program. Although few exact criteria can define patients who are not eligible, several considerations and screening scales can help determine a particular patient's suitability. Specific attention must be given to right heart function, neurologic status, existing infections, renal function, and transplantation suitability. The future of this field will not only be in technological advances with devices but in optimization of patient selection and expanding indications such as permanent replacement therapy.