This study was designed to investigate the intratester and intertester reliability of isokinetic ankle inversion and eversion-strength measurement in neutral foot position in healthy adults using the Biodex dynamometer. Twenty-five men and women performed five maximal concentric contractions at 60 and 180degrees/s angular velocities. Two physicians tested each subject. The first physician applied the test four times, and the second physician three times. Reliability of peak torque was assessed by calculating the intraclass correlation coefficient (ICC). At both angular velocities, inversion strength was greater than eversion, and when the angular velocity was increased, inversion and eversion strength were decreased, as tested by both physicians. The first measurements of inversion and eversion strength of the first physician were significantly lower than the other measurements (p<0.01). The intratester ICCs for ankle inversion in healthy young adults were highly reliable (ICC 0.92-0.96), and for the eversion values ranged from 0.87 to 0.94. Intertester ICCs for ankle inversion and eversion peak torque values demonstrated a value of 0.95. Isokinetic tests of ankle inversion and eversion strength at 60 and 180 degrees/s angular velocities in neutral foot position for healthy adults are highly reliable with the Biodex dynamometer.