Sensory processing goes on during sleep;exteroceptive information, whatever the sensorial modality, is transferred from periphery to primary cortical areas, and sensory discrimination is preserved;the lack of behavioural responsiveness and memory recollection of the stimuli during sleep suggest differences relative to wakefulness.The continuity theory of dreaming implies important relations between awake and dreaming cognition.Furthermore it is conventionally accepted that our sensory feelings result from previous experiences.Dreams are hallucinatory experiences;in them sensory experiences, except for vision, are infrequent.Therefore it is expected that those with important sensory deficits, do not include them in their dreams, mostly for those with congenital defects, such as, congenital deaf and blind.Dream content evaluation together with neurophysiologic methods in these populations showed different results, namely dreams contents including auditory and visual stimuli, together with the expected neurophysiologic changes.Furthermore dream contents studies in subjects with acquired sensory deficits, such as stroke and other neurologic patients are presented.The hypothesis of a brain sensory library, independent of previous experienced and present at birth, is discussed.