Myoclonus refers to brief muscle jerks caused by neuronal discharges. Etiologies are numerous, ranging from physiological jerks to myoclonus secondary to severe neurodegenerative conditions. The source of myoclonus may be in the cerebral cortex, the brain stem or the spinal cord and multiple generators may be involved in a single patient. The clinical approach to myoclonus relies on both etiological and physiological classifications. Pharmacological therapy is largely based on the presumed site of origin of myoclonus. Polytherapy may be required, particularly in severe cases of cortical myoclonus.