Study Design: Case control study. Objective: To determine the main risk factors for pressure ulcer (PU) in ambulatory spinal cord injury (SCI) patients. Setting: Hospital del Trabajador, Santiago, (ACHS (Chilean Security Association), Chile. Methods: We studied 41 patients for traumatic SCI, from Santiago, Chile, cared for in our hospital. The clinical histories were reviewed from first discharge to 1996. The patients were categorized into two groups: 18 cases with a previous history of PU, and 23 patients with no history of PU were considered as controls. Univariate analysis was performed, 18 variables per case, 10 of which were psychosocial factors. Results: There were 37 men and four women. Average age was 41.7 years. Duration of SCI on average was 6.7 years. The distribution was complete paraplegia (CPP) 22 patients (54%), complete tetraplegia three patients (7%), incomplete paraplegia 11 patients (27%) and incomplete tetraplegia, five patients (12%). Four variables of the univariate analysis were significant: duration of cord injury (SCI time) >5 years, completeness of cord injury, paraplegia and not able to practice regular standing. There was a significant association in body morphology (endo or ectomorphic), being able to practice regular standing and personality disorder in CPP. Conclusions: The risk for developing PU was 4.3 times greater in CPP patients than is any other type of SCI. CPP patients who do not practice standing periodically, who have a personality disorder and have an ecto/endomorphic corporal morphology have a greater risk of suffering PU.