A common side effect of the pharmacotherapy for treatment of the movement disorder Parkinson’s disease is the development of l -DOPA-induced dyskinesia (LID). These are abnormal, involuntary, choreic and dystonic movements that can be very debilitating, and therefore new treatment options are sought. LID can be modelled in rodents (rats and mice) with a unilateral 6-hydroxydopamine lesion by chronic administration of l -DOPA. This chapter provides a detailed description of the most commonly used rating scale for abnormal involuntary movements in rodents as well as experimental considerations important for setting up this model.