Glucose intolerance occurs frequently in patients with spinal cord injury (SCI). To characterize this better, 45 patients with spinal cord injuries received oral glucose tolerance tests (OGTT). The subjects with glucose intolerance had significantly higher insulin levels than either the glucose-tolerant or normal control subjects. Since hyperinsulinism in the presence of glucose intolerance suggests insulin resistance, the peripheral insulin activity (A) was calculated from the OGTT data. The glucose-intolerant SCI patients had significantly lower A values than the other groups. The most resistant SCI subjects (A125I-insulin binding to SCI patients' circulating monocytes was not significantly different from that in control subjects.