The aim of the present study was to compare sleep patterns prior to and following prolonged total sleep deprivation (205 hr) in 4 subjects. Following 205 hr of deprivation, the percentages of Stage 4 and the rapid-eye-movement stage of sleep were increased while the percentage of Stage 2 sleep was decreased on all 3 recovery nights. On the first 2 recovery nights, marked alterations in rapid-eye-movement sleep were noted in addition to the increases in rapid-eye-movement stage percentage, including 2 sleep onset rapid-eye-movement periods, decreased rapid-eye-movement latencies, and decreased rapid-eye-movement intervals between earlier rapid-eye-movement periods. These alterations were most marked in the subject who experienced the greatest psychologic disturbance during the deprivation period. Differences in Stage 4 and rapid-eye-movement stage rebounds as well as the possibility of a relationship between certain psychologic disturbances and rapid-eye-movement pattern alterations are considered.