This study was an attempt to evaluate tie relaxation potential of the flotation environment, employing both subjective, and objective measures. The subjects were 20 male and 20 female adult volunteers who were floated in a commercially produced tank for up to 150 minutes for each of three runs at intervals of one week. Physiological monitoring of heart rate was done just before and just after each run and during all the flotation periods. Most subjects remained for about 2/3rds of possible time in tank. Heart rate appears to follow a general trend across and within floats starting at a higher value, proceeding to a lower value, and then increasing again. Post-run differences in subjective indices of well-being, relaxation, or anxiety appear to be associated with the age and sex of subjects. Thus, while this environment does seem generally to be a relaxing one, the degree of relaxation potential is related to individual subject differences. These findings will be generalized to other environmental manipulations which may e related to subjective evaluation of increase in sense of well-being and objective indications of relaxation.