Anti-glutamic acid decarboxylase (GAD) antibody-associated ataxia is a rarely diagnosed but potentially curable disease associated with autoimmune damage to and death of Purkinje cells in the cerebellar cortex. In Russia, the authors have provided for the first time descriptions of three own observations of this disease, which had a number of clinical features, such as slow progression, mild ataxia, stroke-like episodes with stem symptoms, concomitant gluten sensitivity, onset of ataxia after hepatitis C with cerebellar hemiataxia and hemiatrophy. In the all patients, the diagnosis was verified based on the determination of high anti-GAD antibody titers in serum and cerebrospinal fluid. All the patients lacked intrathecal synthesis of oligoclonal antibodies; protein levels and cytosis were normal. Pulse therapy with methylprednisolone at a total dose of 3–5 g led to a slight reduction in ataxia in one case (a female patient with subacute onset of the disease); the treatment was ineffective in two other cases (patients with a primary chronic course). The paper analyzes the literature covering the pathogenesis and clinical presentations of this type of ataxia, and difficulties in its diagnosis and treatment.