This chapter seeks to familiarize the readers with sensory assessment. Sensory integrity is the ability to organize and use sensory information. Alteration in sensory function occurs with normal aging. Sensory system is classified into superficial sensation, deep sensation, and combined cortical sensation, whereas sensory receptor is classified into mechanoreceptors, thermoreceptor, nocioceptors, and chemoreceptors. Pain that arises from the skin and muscles or peripheral nerves themselves is defined as somatic pain. Deep pain is accompanied by a definite autonomic response associated with sweating and nausea, changes in blood pressure and heart rate. Referred pain is a painful sensation at a site other than the injured one. The pain is not localized to the site of its cause (visceral organ) but instead is localized to a distant site. Acute pain arises from activation of nociceptors for a limited time and is not associated with significant tissue damage. Chronic pain is prolonged pain lasting for months or longer that arises from tissue injury, inflammation, nerve damage, tumor growth, lesion or occlusion of blood vessels. Fibromyalgia is characterized by widespread chronic pain throughout the body, including fatigue, anxiety and depression.