The aim of this study was to evaluate the sensitivity and validity of the Functional Test for Agility Performance (FTAP) in water polo players. Six elite junior (aged 16.33±0.82 years) male players and 65 competitive men (aged 18.1±4.3 years) who were classified in three groups (G1-3), participated in different phases of the test. The scores accomplished in FTAP at two periods (initial and final) were compared. They were correlated with the scores in Sprint/Agility Test and differences between standards of competition (G1-3) were assessed. Performance differences were assessed using the paired t-test and Pearson’s correlation was used to determine the association with agility time in the Speed/Agility Test. Differences between standards of competition were assessed using ANOVA. The final Functional Test for Agility Performance was performed in fewer seconds compared to initial (p=.002, r=.94). No significant correlation was found between Functional Test for Agility Performance and Speed/Agility Test (r=.42, p=.40), as expected and evidencing the discriminant validity. Differences were found between G1 and G3 (p<.001) and G2 and G3 (p=.008). The Functional Test for Agility Performance showed adequate sensitivity and validity, and thus is a decision-making test that can be used to assess training and expertise.