Movement disorders are defined as neurological states presenting with abnormal speed, fluency, quality, and ease of movement. To categorized patients with abnormal involuntary movements, movement disorders should be divided into those with too little movement, hypokinetic and those with too much movement, hyperkinetic. Mainly six movement disorders are recognized and include parkinsonism, chorea/ballismus, tremor, dystonia, myoclonus and tic. However, some movement disorders show very similar, e.g. dystonic tremor v.s. tremor, and some patients may have mixed movement disorders, e.g. dystonia with myoclonus. For understanding the movement disorders, neurologist should be aware need to focus on the speed, frequency, rhythm and localization of involuntary movements. In this chapter, we review how to diagnosis the movement disorders.