The myoclonic epilepsies are a collection of syndromes in which myoclonic seizures are a prominent feature. Proper classification of a patient's syndrome is critical for appropriate treatment and prognosis. However, classification of such syndromes is often difficult because the terminology used to describe seizures can be confusing and inconsistent. Myoclonic epilepsy syndromes can be epileptic or nonepileptic and can also be divided into inherited and acquired forms. Progressive myoclonic epilepsy (PME) syndromes are the most severe of the myoclonic epilepsies. Diagnosis of PME syndromes on clinical grounds can be difficult, but advances in genetic testing have made diagnoses more accurate. Some other benign myoclonic epilepsy syndromes also have identified gene markers, which can aid in diagnosis. To accurately classify a patient's epilepsy syndrome, clinicians should use all available clinical laboratory tools appropriately. Improved accuracy of diagnosis for patients with myoclonic epilepsies should lead to more dependable prognoses and more effective treatment.