This study compared the validity of reported equations as predictors of peak
VO
2 in 8–10-year-old children. Participants (90 boys and girls aged 8–10 years) performed the multistage-shuttle-run-test (MSRT) and peak
VO
2 was measured in field using a portable gas analyser. The equations that estimated peak
VO
2 from the MSRT performance were chosen according to the age range of this study. As follows, the FITNESSGRAM reports and the equations of Leger et al. (Can J Appl Sport Sci 5: 77–84,
1988), Barnett et al. (Pediatr Exerc Sci 5:42–50,
1993), Matsuzaka et al. (Pediatr Exerc Sci 16:113–125,
2004) and Fernhall et al. (Am J Ment Retard 102:602–612,
1998) were used to estimate the peak
VO
2 and compared with the directly measured value. The equation of Leger et al. (Can J Appl Sport Sci 5: 77–84,
1988) provided a mean difference (
d) of 4.7 ml kg
−1 min
−1 and a 1.0 slope. The equation of Matsuzaka et al. (Pediatr Exerc Sci 16:113–125,
2004)(a) using maximal speed (MS) showed a higher
d (5.4) than the remaining using total laps
d (4.2). The equation of Barnett et al. (Pediatr Exerc Sci 5:42–50,
1993)(a) that includes triceps skinfold and MS showed the highest
d (6.1) but the smallest range (24.1) and slope (0.6). Data from the FITNESSGRAM had the smallest
d (1.8 ml kg
−1 min
−1), but also had the highest range between limits of agreement (28.6 ml kg
−1 min
−1) and a 1.2 slope. The lowest slope (0.4) and range (22.2 ml kg
−1 min
−1) were observed using the equation of Fernhall et al. (Am J Ment Retard 102:602–612,
1998). Log transformation of the data revealed that the equations of Matsuzaka et al. (Pediatr Exerc Sci 16:113–125,
2004)(a) (1.1*/÷1.25) and Fernhall et al. (Am J Ment Retard 102:602–612,
1998) (1.17*/÷1.25) showed the closest agreement among all, but they still yield unsatisfactory accuracy.