Head injury is the leading cause of posttraumatic anosmia. Complete or partial loss of olfactory function may occur when the nasal passages are blocked, olfactory nerves are injured or there are contusions or hemorrhages in olfactory centers of the brain. Evaluation of patients with posttraumatic olfactory loss should include a physical examination by the otolaryngologist. Nasal endoscopy and radiological studies should be performed as well as olfactory function tests to determine the degree and type of olfactory impairment. Although treatment options may be limited, physicians should provide information and counseling regarding the risks and hazards associated with loss of olfactory function. For some individuals such as cooks, firefighters, and research scientists, an assessment of vocational activities should be performed prior to reentry into the workplace. Individuals with impaired olfactory function may be unable to detect important warning signs such as gas leaks, volatile chemical fumes and fires and therefore place themselves and coworkers at an increased risk for serious injury or death.