Abstract Background Nurses employed in operating theatres and pathologists are workers professionally exposed to some environmental xenobiotics, such as drugs and formaldehyde (FA). Through experimental and epidemiological studies, both acute and chronic inhalation of FA has been associated with various health effects, including toxicity in the respiratory tract and cancer. The purpose of this study was to evaluate the relationship between occupational exposure to FA and the intensity of oxidative stress (OS). Methods 87 female hospital workers were enrolled in a Turin hospital in Italy. Each subject filled a questionnaire and provided biological samples to measure OS biomarkers: 15-F2t-Isoprostane, malondialdehyde (MDA) and total glutathione content (GSX) in urine and inflammatory mediators and receptors (sIL-6R, VEGF-R2, TNFR1, TNFa, FGF2, CD30, CD27) in blood. All individuals were genotyped for CYP1A1, GSTT1, GSTM1, TNFa, and IL-6 polymorphisms. A personal passive air sampler, worn for a working shift (8h), assessed personal FA exposure. Results Subjects exposed to FA (27%) resulted to have a significant higher amount of 15-F2t-Isop (p = 0.000), MDA (p = 0.000), GSX (p = 0.001) compared with non-exposed workers. FA concentration was positively correlated with prevalence of reported respiratory symptoms (p = 0.004), 15-F2t-Isop (p = 0.044), GSX (p = 0.000), MDA (p = 0.000), FGF2 (p = 0.000), CD27 (p = 0.000) and negatively with sIL-6R (p = 0.001), VEGF-R2 (p = 0.000). A significant reduction was found in GSTT1 positive subjects concerning MDA levels (p = 0.000). The same relationship was found in the control group (b=-2.25; C.I. 0.21 - 0.516; p = 0.06). Conclusions FA exposure is confirmed to be an OS inductor and to be correlated with inflammatory response, highlighting how daily occupational exposure to this air pollutant can result in measurable biological outcomes. Key messages Daily occupational exposure to FA results in a disruption of oxidative status and inflammatory profile. GSTT1 gene polymorphism is able to influence the MDA levels in the control group.