OBJECTIVE To investigate the change of indicators of oxidative stress in serum and NF-kappaB in peripheral blood mononuclear cells of patients with silicosis, and explore the mechanism of the development of silicosis. METHODS The subjects were divided into (1) 200 workers exposed to SiO2 for at least 1 years in a foundry served as the dust-exposure group; (2) 130 cases with silicosis (I phase silicosis 64 cases, II phase 46 cases III phase 20 cases) served as the silicosis group; (3) 32 cases with 0+ phase silicosis in the foundry served as the observed group,(4)100 subjects from a hotel served as the control group. The serum including superoxide dismutase (SOD), nitric oxide (NO), serum glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), nitric oxide synthase (NOS), lipid malondialdehyde (MDA) and NF-kappaB protein levels in peripheral blood mononuclear cells were determined, respectively. RESULTS Compared with the control group, NO levels in dust-exposed group and silicosis group significantly increased, and SOD decreased significantly (P < 0.05 or P < 0.01). Compared with the control group and dust-exposed group, T-AOC, NOS, MDA levels in silicosis group significantly increased (P < 0.05 or P < 0.01). GSH-Px in dust-exposed group and silicosis group were (231.164 +/- 36.484) and (270.469 +/- 39.228)U/ml, respectively which were significantly than that [(223.360 +/- 46.838) U/ml] in control group (P < 0.05 or P < 0.01), and there was significant difference of GSHPx between the silicosis group and the dust-exposed group significantly (P < 0.01) . GSH-Px level [(290.750 +/- 39.129) U/ml] in III phase silicosis group were significantly higher than those [(256.906 +/- 21.41) and (259.594 +/- 34.79) U/ml] in observation group and I phase silicosis group (P < 0.05). NF-kappaB levels [(72.06 +/- 9.12) and (85.25 +/- 11.64) ng/L] in dust-exposed group and silicosis group were significantly higher than that [(59.71 +/- 9.27) ng/L] in control group (P < 0.01), and there was significant difference of between the silicosis group and the dust-exposed group (P < 0.01). There was a positive correlation between serum GSH-Px level and the silicosis stages (r = 0.507, P < 0.01). Also there was a positive correlation between NF-kappaB level and silicosis stages, age, GSH-Px or NO levels (r = 0.376, 0.243, 0.233, 0.221, P < 0.01). CONCLUSION The imbalance of oxidative and anti-oxidation system and the activation of NF-kappaB are related with the occurrence and development of silicosis. The monitoring of oxidative stress indicators and NF-kappaB is beneficial to the prediction and prognosis assessment of silicosis.