The discovery of dystonia as an isolated abnormality or as a symptom involved in a larger neurological or systemic disease is not unfrequent in clinical practice. Dystonia can occur at any age, from childhood to elderly. A rapid diagnosis is very important to optimise the managing of those chronical and often invalidating diseases. We should point out the pre-eminent role played by MRI techniques in the diagnosis and follow-up of dystonic patients. We present here an overview of most frequent dystonic troubles and an attempt of classification to simplify their diagnosis.