ABSTRACTData are presented from some 321 Keeshond dogs attending a clinic for electroencephalographic records, and their 108 close ancestors. They are examined to see whether the EEG readings are diagnostic of a tendency to epileptiform fits, and what hereditary basis there is, if any, for both the readings and the fits. The evidence does not support the idea of a diagnostic value; finds no hereditary basis for the readings; and, as far as the limited information about dogs which have had fits allows, slightly favours some hereditary component in the aetiology of epilepsy. These findings are discussed in relation to those concerning hereditary epilepsy in other breeds.