BACKGROUND: The majority of adults with Generalised Joint Hypermobility experience symptoms such as pain and joint instability, which is likely to influence their gait pattern. Accordingly, the purpose of the present project was to perform a biomechanical gait analysis on a group of patients with Generalised Joint Hypermobility and compare them to a group of healthy subjects. METHODS: Seventeen adults clinically classified with Generalised Joint Hypermobility (6 males and 11 females) and seventeen healthy subjects (9 males and 8 females) were included in the project. The subjects walked across three force platforms while they were filmed by five video cameras. Net joint moments were calculated in 3D by inverse dynamics and peak values were input to statistical analyses. A 3D knee joint model was used to calculate bone-on-bone forces. FINDINGS: In the frontal plane both the peak knee and hip abductor moments were 13% higher in the patient group. In the sagittal plane the peak knee extensor moment was 10% higher for the patients and the flexor moment about the knee joint in the middle of stance was 27% lower for the patients. Increased flexion in the knee joint for the patients was also observed. INTERPRETATION: The finding that adults with Generalised Joint Hypermobility display higher joint moments during walking in both the frontal and the sagittal planes and increased knee joint loadings may explain the pain symptoms in the patient group and indicate these subjects are subjected to an increased risk of developing osteo-arthritis.