Cerebellar ataxias represent a heterogeneous group of neurodegenerative disorders. Two main categories are distinguished: hereditary and sporadic ataxias. Sporadic ataxias may be symptomatic or idiopathic. The clinical classification of hereditary ataxias is nowadays being replaced by an expanding genotype-based classification. A large spectrum of degenerative and metabolic disorders may also present with ataxia early or late in the course of disease. We present a diagnostic algorithm for the adult patient presenting with subacute cerebellar ataxia, based on family history and straightforward clinical characteristics of the patient. Along with the algorithm, an overview of the autosomal dominant, autosomal recessive, X-linked, mitochondrial, symptomatic and idiopathic subtypes of cerebellar ataxia is presented. An appropriate diagnosis is of utmost importance to such considerations as prognosis, genetic counselling and possible therapeutic implications.