The role of dreaming in the assimilation and mastery of new experiences was examined in this study. Previous work had shown that a film of an autopsy can evoke measurable psychologic and physiologic indices of anxiety. Adaptation to the experience was indicated by lower levels of anxiety during a second viewing of the film. We examined the effect of dream (Stage REM) deprivation on adaptation to the second viewing. Between the first and second viewings, 9 subjects were dream deprived, 5 had normal sleep and 6 were awakened from non-REM sleep. For those who showed a significant anxiety response to the first viewing, the dream deprived group showed significantly less adaptation to the second viewing than the other two groups. These results support the hypothesis that dreaming aids adaptation to anxiety-provoking stimuli.