International audienceSleep disruption is frequently reported by people with idiopathic environmental intolerance attributed to electromagnetic fields or IEI-EMF. The physiopathology of this association is not clear. We aimed to evaluate whether melatonin level was affected in IEI-EMFs patients. Melatonin levels in saliva and urine were quantified by immunoassay techniques in a session without intentional exposure to EMF. Sleep quality was assessed by questionnaires.Significant differences in PSQI and ESS scores between compared groups were observed. Likewise, a higher proportion of pathological sleep for ESS was found in IEI-EMF group. Results indicate that melatonin is not associated with different sleep troubles reported by IEI-MFs patients