Various aspects of verbal memory in patients with Huntington's disease (HD) were studied using the California Verbal Learning Test (CVLT). We tested if the level and interplay between 5 parameters of different memory mechanisms and processes were sufficiently specific to allow acceptable discrimination between patients with HD, patients with Parkinson's disease (PD), and patients without known CNS disease or injury. The HD-patients were characterized by a deficit in acquisition, elevated rates of recall errors and increased use of a passive learning strategy. Preserved aspects were shown in retention over time, interference effects and recognition relative to recall. Employing multivariate classification and validation techniques, the 5 CVLT-features demonstrated good separability between the HD-patients and the control patients. Qualitative similarities between subgroups were suggested, but more disease-specific data seemed necessary in further studies. A number of findings suggested a defect in the active organization of items to be encoded and recalled in HD. Similar findings in the PD-group might indicate that this trait is common in several types of 'subcortical dementia'.