OBJECTIVE: To assess differences in glenohumeral joint rotatory range of movement in javelin throwers between the throwing and non-throwing arm. METHOD: A universal 360 degrees goniometer was used to assess glenohumeral joint external and internal rotation range in 90 degrees of shoulder abduction in a group of ten senior international javelin throwers. RESULTS: Both arms had significantly greater degrees of external than internal rotation (p < 0.01), and the throwing arm had significantly greater range of external rotation than the non-throwing arm (p < 0.01). CONCLUSIONS: The presence of an excessive range of external rotation in the throwing shoulder has the potential to increase eccentric load on the rotator cuff muscles and strain on the passive restraints of the glenohumeral joint. Both of these factors have been implicated in the pathological processes leading to injury in the overhead throwing athlete.