Peripheral nerve injuries usually lead to devastating loss of motor, sensory, and autonomic functions in the patients. Due to the complex requirements for adequate axonal regeneration, functional recovery is often poorly achieved. Experimental models are a useful tool to investigate the mechanisms related to axonal regeneration and reinnervation and to test new strategies to improve functional recovery. Therefore, objective and reliable evaluation methods should be applied for the assessment of regeneration and function restitution after nerve injury in animal models. Electrophysiological tests are commonly used in clinical practice and can be also performed in animal models to determine the nature of peripheral nerve disorders, their severity, and their evolution. These tests provide an integrated approach using sensory and motor nerve conduction studies and electromyography, spinal reflex tests, and motor and sensory evoked potentials if appropriate. The low-invasiveness of several electrophysiological methods allows serial evaluation of sensory and motor reinnervation distal to the injury site at desired intervals without killing the animals or disturbing the regeneration process. This chapter gives a brief review of the most useful electrophysiological methods, their values, and limitations. © 2009 Elsevier Inc. All rights reserved.