The sleep characteristics and the body positions of four men and four women ranging in age from 65 to 75 yr. were monitored in the laboratory for 2 consecutive nights preceded by 2 adaptation nights. Overall, there was an average of 16 position shifts per night with duration of position averaging 33 min. The preferred trunk positions were on the right side (55%) and the least frequent on the stomach (2%) and limited to waking episodes. Back positions occurred for 19% of sleeptime and left positions for 22%. The preference for the right side and the absence of stomach postures during sleep which appear to be characteristic of elderly persons may respectively be related to cardiovascular and respiratory functions.