The purpose of this study was to develop a simple and convenient indirect method for estimating maximal oxygen uptake (VO_2max) and oxygen uptake at the anaerobic threshold (VO_2AT) by using workrate and a rating of perceived exertion (RPE) during a submaximal graded cycling test (GCT_submax). One hundred and fifty-four healthy Japanese men, aged 20 to 64 years, volunteered to participate in the study. The subjects were randomly divided into two groups, a validation (V) group (n=100) and a cross-validation (CV) group (n=54). The V and CV groups performed a maximal cycling test and the GCT_submax. The GCT_submax was conducted with documentation of three categories (overall, chest, legs) of RPE, up to a rating of 15. Prediction equations of VO_2max and VO _2AT were developed by multiple regression analysis using data of the V group. The mean VO_2max and VO_2AT of the V group were 2462 ± 484 ml·min^-1 and 1349 ± 334 ml·min^-1, respectively. Correlational analyses indicated that the workrate (W) at which the legs RPE (RPE_legs) reached 15 or higher was evaluated first (W _{RPE legs 15}) together with W _{RPE legs 14} both yielded the highest correlation coefficients (r) with VO_2max (r=0.781) and VO_2AT (r=0.790), respectively. The developed prediction equations of VO_2max and VO_2AT were VO_2max (ml·min ^-1) =1.19W_{RPE legs 15} (kgm·min^-1) - 15.84age (yr) + 13.06 weight (kg) + 1365 (R=0.849, SEE=261 ml·min ^-1) VO_2AT (ml·min^-1) = 1.34W_{RPE legs 14} (kgm·min^-1) -5.49 age (yr) + 665 (R=0.816, SEE=195 ml·min^-1) Results of a cross-validation analysis indicated a similar estimation (r=0.793 and 0.853, and SEE=240 ml·min^-1 and 183 ml·min^-1) compared with the above equations developed from data of the V group. Reliability coefficients of VO_2max (r=0.891) and VO_2AT (r=0.870) respectively were significant and there was no difference in the mean value between trials 1 and 2. The "RPE method" developed for estimating cardiorespiratory fitness is not only a unique indirect method but also a valid and useful tool in various settings of exercise prescription.