The clinical management of cerebellar ataxia is challenging, mainly because ataxia is a symptom of many neurological diseases. Many types of ataxia disorders are genetic and some are extremely rare. Here, the authors suggest a diagnostic approach to ataxia developed around a case of sporadic, late-onset, slowly progressive ataxia. Clinical information such as age of onset, rate of progression, family history and certain non-cerebellar features can narrow the differential diagnosis. Brain MRI is almost obligatory and may reveal valuable diagnostic clues. Having ruled out structural lesions, the two other most common diagnoses are inflammatory and degenerative (including genetic) disorders. Although only a minority of underlying diseases are treatable, there are still many options for supportive care.