Inpatient neuropsychologists play a fundamental role in the evaluation and treatment of patients with acquired brain injury (ABI), including both traumatic brain injury (TBI) and acute stroke. Through monitoring, assessing, and treating complex cognitive and behavioral sequalae, neuropsychologists work to address complex challenges while serving diverse neurological presentations in the context of clinical and administrative demands. This chapter will focus on the relevant clinical issues surrounding ABI including identification of brain injury mechanisms, determination of severity of injury, medical management, and considerations for cognitive assessment during acute recovery. We will also provide guidance for provision of feedback and education to the treatment team, patient, and family during this critical time.