BACKGROUND: Magnesium sulphate (MgSO4) is the only treatment approved for fetal neuroprotection. No information on its use is available in the absence of a national registry of neonatal practices. The objective of our study was to evaluate the use of MgSO4 for fetal neuroprotection in French tertiary maternity hospitals (FTMH). METHODS: Online and phone survey of all FTMH between August 2014 and May 2015. A participation was expected from one senior obstetrician, one senior anaesthetist and one senior neonatologist from each FTMH. Information was obtained from 63/63 (100%) FTMH and 138/189 (73%) physicians. Use of MgSO4 for fetal neuroprotection, regimen and injection protocols, reasons for non-use were the main outcome measures. RESULTS: 60.3% of FTMH used MgSO4 for fetal neuroprotection. No significant difference was observed between university and non-university hospitals or according to the annual number of births. Protocols differed especially in terms of the maximum gestational age (3% <28 WG, 71% <33 WG, 18% <34 WG and 8% < 35 WG). Eighty seven percent of centers using MgSO4 prescribed retreatment when necessary, but according to non-consensual modalities in terms of number of treatments or between-treatment intervals. Injections and monitoring were mostly performed in the delivery room (97%) but also in the recovery room in one half of hospitals. Lack of experience (52%), absence of a written protocol (49%) and national guidelines (46%) were the reasons most commonly reported to explain non-use of MgSO4 as a neuroprotective agent. CONCLUSIONS: Sixty percent of FTMH used MgSO4 for fetal neuroprotection, but according to heterogeneous regimens. National guidelines could allow standardization of practices and better MgSO4 coverage.