Background and Objective: Phthalates and other plasticizers are extensively used in medical devices (MD) from which they can release and contaminate the patients. This exposure may be associated with reproductive and neurodevelopment disorders (1,2) (some phthalates are endocrine disruptors (ED)). Newborns in Neonatal Intensive Care Units (NICU) are at high risk due to a higher exposure to plasticizers (3–9), a reduced ability to detoxify these contaminants (10) and a higher sensitivity to ED (11). Setting and Method: We conducted a multicentric biomonitoring study (ARMED NEO project) to assess and compare the urinary levels of DEHP (di-(2-ethylhexyl)phthalate), DEHTP (di-(2-ethylhexyl)terephthalate) and TEHTM (tri-(2-ethylhexyl)trimellitate) metabolites as biologic markers of this exposure during and after newborns’ stay in NICU. Main outcome measures: Daily urinary samples in NICU for a maximum of 14 days and a last sample in the neonatalogy unit 24 to 48 h before hospital discharge were collected for each patient. MD sources and exposure factors were also investigated by recording all PVC MD used, age, gender, body weight, type of incubator. Results: 508 urinary samples from 97 patients (center 1/C1 and center 2/C2) were collected. Exposure of newborns to DEHP was 5 to 10 times higher than that of DEHTP and 50 times higher than that of TEHTM (median of the sum of metabolites: DEHP-C1:276.99; C2:389.68 μg/mmoL; DEHTP- C1:51.53; C2:36.78 μg/mmoL; TEHTM- C1:5.08;C2:1.48 μg/mmoL). DEHP and TEHTM metabolites urinary concentrations were significantly lower at discharge than in NICU(18/35-fold decrease for DEHP;4/eightfold for TEHTM, respectively for C1/C2). DEHTP metabolites concentrations were similar. MD used for respiratory assistance, infusion therapy, enteral nutrition and transfusion were the main sources of exposure. Smaller gestational age and body weight, and closed incubators significantly increased the exposure of newborns. Conclusion: Additional efforts are necessary to promote a substitution of DEHP in MD by safer alternatives such as TEHTM and DEHTP, especially for respiratory assistance MD and MD having a contact with blood (i.e. transfusion, ECMO).