To investigate the relationship between pain threshold and oxidative stress levels in patients with acute and chronic inflammatory or non-inflammatory back pain. A total of 137 patients were recruited for the study, including 33 acut back pain (32 lumbar disk herniation, 1 lumbar spondilosis) (16 men, 17 women), 35 with chronic back pain (33 lumbar disk herniation, 1 lumbar spondilosis, 1 sacralisation) (16 men, 19 women), 34 with ankylosing spondylitis (21 men, 13 women) (AS) and 35 without any back pain (15 men, 20 women). The visual analogue scale (VAS) was used to evaluate pain levels and algometry was used to evaluate the pain threshold in all cases. In addition, serum malondialdehyde (MDA) levels were assessed in all patients. The mean ages for groups 1, 2, 3, and 4 were 40.3±10.3, 39.9±9.7, 40.6±10.4, and 38.5±8.1 years, respectively. There was no significant difference between the ages of the groups (p=0.851) (Table 1). The VAS scores of all groups were significantly higher compared to the control group. Particularly, the acute and chronic back pain groups had significantly higher VAS scores than those of the AS group. All three back pain groups had significantly higher serum MDA levels compared to those of the control group (p<0.01). Moreover, serum MDA levels of acute back pain group were significantly higher than the chronic back pain and AS groups (p=0.004 and p=0.032). Pain threshold levels of the acute and chronic back pain group were significantly lower compared to the control group (p=0.002 and p=0.001). In contrast, the pain threshold levels of the AS group were higher than the control group. Oxidative stress levels in patients with inflammatory and non-inflammatory back pain are higher than in the controls, which suggests that oxidative stress may be involved in the etiopathogenesis of these diseases. Interestingly, the pain threshold levels in AS patients were found to be higher, which indicates an ongoing desensitization process in these patients.