We have four cases of conduction aphasia to report.     From a detailed neuropsychological analysis, we have subclassified conduction aphasia into three types.     Case I : a 64 year old, right-handed man.     He had showed the feature of aphasia similar to that of motor aphasia at the onset. He had severe difficulty in conversational speech. He had serious problems in naming and was prone to repetition. The difficulty in naming was greater than the difficulty of repetition. Conversational speech, naming and repetition contained abundant literal paraphasias.     Case II : a 59 year old, right-handed man.     He was chracterized by the following clinical picture : great impairment of spontaneous speech in contrast to good auditory comprehension, disturbance of repetition, abundant literal paraphasias in spontaneous speech and repetition, literal paralexia, and a large amount of literal paragraphias. Naming was invariably poor, with defects identical to those in repetition.     Case III : a 65 year old, right-handed man.     Case IV : a 68 year old, right-handed housewife.     They had all exhibited the feature of aphasia similar to that of sensory aphasia at the onset and had a poor comprehension of spoken language. The problem of repetition was greater than the naming disability. Although the auditory comprehension improved soon, there was little improvement of the disturbance of repetition.     As the auditory comprehension improved, the patients recovered to an anomic stage in which abundant literal paraphasias in spontaneous speech, naming and repetition was reduced. Ideomotor apraxia and constructive apraxia was present mildly.     We have subclassified conduction aphasia as follows,     1. Broca (anterior) type: Case I     2. typical type: Case II     3. Wernicke (Posterior) type: Case III, IV     We consider that the basic syndromes of conduction aphasia are literal paraphasia in spontaneous speech, naming and repetition. We also feel that conduction aphasia preserves word concepts, but in uttering the demanded word, there is a disorder in adequate selection and arrangement of phonemes in sequence, a disturbance at the level of phonemic programming.