This research involves the relative value of liquid crystal contact thermography (LCT) as compared to the physical examination, myelography, electromyography and CT scanning in the examination of 155 chronic low back pain patients. Thermograms were interpreted by two independent examiners as positive for nerve root compromise. Results demonstrate excellent interobserver reliability when used for this specific purpose and respectable correlations with the physical examination and EMG studies were obtained. Somewhat less correlation was found between LCT and the diagnostic procedures of CT scanning and myelography, especially in the postoperated patient. Liquid crystal contact thermography shows some promise as an adjunctive diagnostic tool in the assessment of chronic back pain patients with radicular symptoms, especially where further surgery is contemplated and the more structural tests of CT scanning and myelography may be falsely positive as a result of previous back surgery.