This study aimed to determine the rating of perceived exertion (RPE) values corresponding to the blood lactate concentration (BLC) training zone boundaries (2 and 4 mmol.L) in moderately trained runners using the Borg CR-10 scale. Moderately trained runners (n = 95) performed a submaximal incremental test on a treadmill, recording BLC and RPE at every stage. Simple linear regression analysis was used to determine the RPE values corresponding to the BLC training zone boundaries, which revealed that RPE was significantly and strongly correlated with BLC (r= 0.821; P< 0.001; R= 0.675; adjusted R= 0.674; standard error of estimate= 1.18). The prediction equation (RPE= 1.092 × BLC + 2.143) was obtained and RPE values at the BLC training zone boundaries of 2 mmol.L and 4 mmol.L calculated as 4.3 (95% CI, 3.9-4.7) and 6.5 (95% CI, 6.0-7.1), respectively. In conclusion, the RPE values at the BLC training zone boundaries of 2 mmol.L (4.3) and 4 mmol.L (6.5) were adequately predicted. RPE (4.3 and 6.5) can be used as an affordable tool for controlling intensity in order to maintain the athletes in prescribed zones during training sessions.