To analyse the effect of fatigue of the peroneal muscles on ankle joint position sense (JPS) in various angles of inversion and eversion.Repeated measures design.University exercise laboratory.Thirty-five subjects (male: n=10; female: n=25), age range 19–36 years with no injury to the right ankle in the past 2 years, no neurological deficits, ankle or foot orthopaedic disorders, balance disorders, or disorders of vision not correctable by glasses.Joint position sense error of active target angle before and after a fatiguing exercise programme of the peroneal muscles using an isokinetic dynamometer.Fatiguing exercise of the peroneal muscles did not significantly alter JPS error at the three target angles (90° inversion: −0.3±7.6 to −2.2±7.2°; 20° inversion: 4.7±5.5 to 2.8±6.3°; 90° eversion: 0.5±3.8 to −0.2±7.2°; P<0.05).Fatigue of the peroneal muscles did not affect ankle JPS, suggesting that either proprioception is fatigue resistant in the peroneal muscles or other structures in the ankle (e.g. ligaments, capsule) may play a significant proprioceptive role.