Spinal cord injury (SCI) causes inactivation and consequent unloading of affected skeletal muscle and bone. This crosssectional study investigated correlations of muscle and bone in spinal cord-injured subjects compared with able-bodied subjects. Thirty-one complete SCI paraplegics were divided according to the neurological level of injury (NLoI) into group A (n ¼ 16, above thoracic 7 NLoI, age: 33 ± 16 years, duration of paralysis (DoP): 6 ± 6 years) and group B (n ¼ 15, thoracic 8-12, age: 39±14 years, DoP: 5.6±6 years), compared with 33 controls (group C). All were examined with peripheral quantitative computed tomography at 66% of tibia length (bone and muscle area, bone/muscle area ratio). In ablebodied subjects, muscle area was correlated with bone area (Po0.001, r ¼ 0.88). Groups A and B differed significantly from the control group in terms of bone and muscle area (Po0.001). In paraplegics, less muscle per unit of bone area (bone/muscle area ratio) was found compared with controls (Po0.001). Bone area was negatively correlated with the DoP in the total paraplegic group (r ¼ À 0.66, Po0.001) and groups A and B (r ¼ À 0.77, P ¼ 0.001 vs r ¼ À 0.52, P ¼ 0.12, respectively). Muscle area and bone/muscle ratio area correlations in paraplegic groups with DoP were weak. Paraplegic subjects who performed standing and therapeutic walking had significantly higher bone area (P ¼ 0.02 and P ¼ 0.013, respectively). The relationship between bone and muscle was consistent in able-bodied subjects and it was predictably altered in those with SCI, a clinical disease affecting bone and muscle.