Although most of scientific knowledge in dream research is based on young adult studies, this article provides a review of the effects of normal and pathological aging on dream psychology. It starts with preliminary comments about epistemological and methodological principles of dream research, its singularities in aged persons, and the modifications of sleep physiology with age. The whole literature agrees that dream recall progressively decreases from the beginning of adulthood - not in old age - and that dream reports become less intense, perceptually and emotionally. This evolution occurs faster in men than women, with gender differences in the content of dreams. The chronological modifications could be explained partly by changes in lifestyle and attitude towards dreams in early adulthood, but mainly by modifications of sleep physiology, particularly the decrease and qualitative changes of rapid eye movement (REM) sleep. Dreams have usually little subjective importance in the mental life of aged persons. However, working with dreams can be a valuable tool for psychotherapy in the aged. According to the few existing data, patients suffering degenerative dementia dream much less than healthy aged persons. In Alzheimer's disease, this could be linked to the decrease of REM sleep, and atrophy of associative sensory areas of the cerebral cortex. Most studied aspects of dreaming in degenerative cognitive disorders are REM sleep behavior disorders, and nightmares induced by cholinesterase inhibitors. More studies are needed to better characterize the evolution of dreams with age, particularly studies performed in sleep laboratory.