Steroid-responsive meningitis-arteritis is an immunopathological disease in dogs characterised by neck pain, pleocytosis of the cerebrospinal fluid (CSF) and increased serum and CSF immunoglobulin (Ig) A levels. A long-term treatment protocol (four to 20 months) with prednisolone was applied in 10 dogs with the condition. Clinical side effects, changes in blood and CSF values and long-term outcome were evaluated retrospectively. Eight of the 10 dogs were without clinical signs up to 29 months after the treatment was terminated. Long-term glucocorticosteroid treatment appears to result only in mild clinical side effects, such as polyuria/polydipsia, polyphagia and weight gain. All clinical and laboratory changes were reversible after the therapy was discontinued. Elevated serum and CSF IgA levels did not decrease to normal values during prednisolone treatment and were still slightly increased after the therapy was discontinued. A marked decrease in the cell count of the CSF was observed after therapy was initiated, although pleocytosis increased again during relapses of the disease. Monitoring of CSF cell count in dogs with this condition seems to be a sensitive indicator of success of treatment. In addition, older dogs with high IgA levels in the CSF and frequent relapses seem to require a longer duration of therapy and have a less favourable prognosis long term. The reason for high systemic and intrathecally produced IgA levels remains unknown, but seems not to be influenced by prednisolone treatment.