No known research has attempted to quantify proprioception of the lower back or to examine the relationship between injury and proprioception in this region. The primary purpose of this study was to explore relationships between low back injury and proprioception of the lower back. Subjects were 88 working male firefighters from public emergency medical service departments. Three types of lower back proprioception (passive motion threshold, directional motion perception, and repositioning accuracy) were tested. Each type of proprioception was examined in the three primary planes of motion using a device designed by the author. Some anthropometric and personal variables were statistically controlled. All variables underwent multiple correlation analysis. The primary findings were: 1) longevity factors [age (r = .30, p < .01) and years of experience (r = .35, p < .001)] were best correlated with proprioceptive deficits in the sagittal plane; 2) injuries were correlated (p < .05) with proprioceptive deficits in the coronal (r = .22) and sagittal planes (r = .17) and with deficits in multiple planes (r = .19); 3) proprioceptive asymmetries were associated with injuries; and 4) the factor most highly correlated with the history of low back injuries was the presence of a spinal disorder (r = .40, p < .001). Impaired proprioception resulting from injury may degrade lumbar motor function, increasing workers' risk of reinjury. Restoring proprioception of the lumbar spine after injury should be a goal of treatment.