The purpose of this study was to identify, using multiple regression analysis, the contribution of differentiated ratings of perceived exertion to overall exertion (RPEO) in women while swimming. Ten female subjects swam at submaximal and maximal intensities and the variables measured included oxygen uptake (VO2), heart rate (fc), ventilation (VE), breathing frequency, tidal volume, blood lactate concentration ([la-]b), RPEO, and four differentiated RPE. These four differentiated RPE were cardiac frequency rating (RPEC), respiratory frequency rating (RPER), arm rating (RPE(arm)), and leg rating (RPE(leg)). These variables used the following equation based on VO2 - R = a + c.(S-b)n, where R was the response to increasing exercise intensity (S) and a, b, and c were constants. The exponents (n) of fc, VE and [la-]b were approximately 1.0, 2.0 and 3.3, respectively. The estimated exponents of RPEO, RPEC, RPER, RPE(arm) and RPE(leg) were approximately 2.4, 2.3, 2.2, 2.5 and 2.5, respectively. There was a highly significant relationship between the four differentiated RPE and their associated physiological responses. The results of this study showed that these interrelationships were clearly delineated. As the percentage maximal oxygen uptake (% VO2max) increased, the major contributing factor to RPEO changed. The RPEC was found to be the main contributing factor from 20% to 45% VO2max, but ceased to contribute beyond 50% VO2max. Above 45% VO2max, RPE(arm) was the major influence, and RPER was the secondary influence from 66% to 96% VO2max. The RPE(leg) was the secondary contributing factor only from 27% to 35% VO2max. It was concluded that differentiated RPE contribution was dependent upon the intensity of exercise in women while swimming.